Bosch combi

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Old 11-18-12, 09:29 PM
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Bosch combi

Oh I doubt anyone will answer tonight....But hopefully before I go in tomorrow....

I have been called back to active duty. The devastation in NJ is horrendous from sandy..
( I have not worked since 09 and am out of retirement because of the need...)

Anyway barrier island gent wants combi boiler. I mounted on wall today and did various gas and copper work. Cut out old Hydrotherm and HWH...etc.

Anyway I need help.

Here is the piping manual.

http://www.bosch-climate.us/files/20...al_07.2011.pdf

I am doing page 57 with three zones.

Questions:

  1. The close space tees show 1 1/4 for the system side, but it only shows 1 1/4 as a concern for the supply. Can I do all 3/4 for the return to the 1 1/4 tee?
  2. The close space tees say 4 pipe lengths max. It says 3/4 min from the unit but unit is 1" threads. So, ok I will run 1". Yeah? No? But coming off the unit straight down is wider then 4 pipe lengths. I assume I need to pipe the tees as close as possible, right? I assume that the best I can do and offset as needed?
  3. In relation to #2 the diagram on page 58 shows 1 1/4 min for the supply. I assume I need 1 1/4 for the close space tees? Does not show on return...
  4. With that said above I will run 1 1/4 to the cic then 3/4 to the zones on the other side of circ. ( Only about 2 ft 1 1/4.) I was thinking making it all 1" since its 1" from the feed and return. Why do I need 1 1/4"?
  5. How much 1 1/4 do I need though if so, or 1 " if I chose that route? I would think I take the larger pipe to the manifolds they show?


97 ft of element only, and cant make it all one loop which was my plan. I am doing ODR with the module on the boiler and three t stats. 403 taco etc....


I am good on all except the close tee issue.


Oh LWCO i am installing just at top lever with boiler. OK?
Feed and exp tank calls for AAV. The unit has one internally. I will skip that. Is OK you think? Page 58

Thats all I can think of.
 

Last edited by lawrosa; 11-18-12 at 09:54 PM.
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Old 11-19-12, 05:56 AM
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Thanks TO,

You can run 1" from the boiler,
The connection from the boiler is 1". Should I reduce to 3/4 to the tees?

And the system is 3/4. Cant I just use 1" close tees? Then reduce to 3/4 at the headers?
 
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Old 11-19-12, 05:59 AM
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From the pic on the manual on pg 57, I would say they are just saying the system loop should be min 1 1/4" both supply and return.
You can run 1" from the boiler, if your loads are light you may find the delta T on the boiler is low. This is not ideal from condensing appliances. And it's 4 of the branch pipe diameters ie 3/4" or 1".
You will always want to keep the system (or primary loop) one pipe size consistantly thoughout.
Make sure your LWCO is above the heat exchanger in the boiler and has an auto vent on top.
 
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Old 11-19-12, 05:59 AM
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Thanks TO,

You can run 1" from the boiler,

The connection from the boiler is 1". Should I reduce to 3/4 to the tees?

And the system is 3/4. Cant I just use 1" close tees? Then reduce to 3/4 at the headers?
Mike NJ

"Marriage is a wonderful institution, but who wants to live in an institution?"

Groucho Marx
 
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Old 11-19-12, 05:47 PM
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I would either use 1" system piping or 1 1/4" system loop.
I would suspect you would be fine with 1" through out.

I assume that the load is light on the boiler, for that reason I might use 3/4" from the boiler to the injection points (closely spaced tees) or add a globe valve in.
This will let you fine tune the boiler flow rate and get some delta T through the boiler ( i have always found that they like 30 degree or so delta T).
Certainly not a must do, but better practice IMHO (for what that's worth).
 
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Old 11-19-12, 06:31 PM
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I piped most today. The pics are from this morning. Also old hydrotherm I ripped out. Everthing was under water some 3ft hence why the customer wants wall hung combi.



Mounted to the wall was a PITA.

I decided to pipe 1" from boiler to injection points. Injection points I made 1" also. Two 1" tees as close togther as I could get spaces them at 3 1/2"

I will run the 1" to the circ and about a ft after the circ ,then reduce to the three zones @ 3/4". Also on the return will be 1 " for another two ft until reduced to 3/4"


Also this unit has a built in expansion tank. I have one I was going to add as an additional tank but possibly I do not need it.

Can anyone help me understand the section that explains if the internal tank is big enough? Im not that smart.

Page 37 and 38 here...

http://www.bosch-climate.us/files/20...Boiler-ISM.pdf

The element is about 100 ft but there is probably another 100 ft of copper. I would say the system holds about 6 gallons???

So fig 9 shows graph line 1 as the default with 7. 25 psi. @ 180f I am good for a system up to 25 gallons???

Thanks...
 
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Old 11-19-12, 07:34 PM
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Damn that manual SUCKS! Where are the piping examples?

I think you're right about the expansion tank, but 'Justin Case' (you know him, right?) says to install a threaded tee someplace where you can install another tank for him.
 
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Old 11-19-12, 07:45 PM
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Here is the piping troop. I am doing page 57

http://www.bosch-climate.us/files/20...al_07.2011.pdf
 
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Old 11-19-12, 08:02 PM
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Ohhhhhh, OK... I take back what I said about the manual. Leave it to them to have a separate manual just for the piping!

I DID think it was kinda weird that there were no piping examples!
 
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Old 11-19-12, 08:25 PM
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Yeah and no piping instruction came with the unit. I had to use what I found online. They only ship with that other manual.

If you read this thread you see I used all 1 " and disregarded the manual suggestion of 1 1/4". The tees will be less the 4" though.

What is your opinion on exp tank? I guess best to install a threaded tee and plug it.
 
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Old 11-20-12, 06:30 AM
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The challenge for locating the expansion tank is to not intefere with the location of the internal one.
I wish they would just not install an internal expansion tank.
You don't really want to points of no pressure change in the system, especially if they work out to be on each side of a circ.
 
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Old 11-20-12, 06:33 AM
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If I add a exp tank it would be on the return. The circ is on the feed.

I am going to do no expansion tank but leave a tee for one.

If you look at all the pipe configs here it seems they only show the exp tank added in high mass pipe layouts. indirect HW, Radiant, solar...etc...

http://www.bosch-climate.us/files/20...al_07.2011.pdf
 
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Old 11-20-12, 06:28 PM
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Well here is what I did...Uggg 4 days installing this thing. But I am by myself. I am doing the wiring now and will be finished tomorrow. Only doing 6 hour days because of family obligations.

HWH side filled.
System filled and purged. ( Only one leak and it wasn't mine...LOL. Old joint leaked from heat...)
Vent needs to be run..etc

Using the taco 403 as a junction box. I think that's OK. I believe that the best I could do with the close tees. Did not install exp tank. Using internal.

Did I tell you all that wiring this thing is a nightmare? Not installer friendly at all.

Will fire up tomorrow.

I will take better pics when I am done... Yes that ugly guy is me.

( That valve where the relief valve goes is temp Just to fill and test. did not have a T&P on me.)
 
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Old 11-20-12, 06:31 PM
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My only sugestion at this point would be to add some shut offs.
Shut off pump flanges for service there, boiler isolation etc.
Maybe some unions at the boiler if it did not have any.
Otherwise looks spot on
 
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Old 11-20-12, 06:35 PM
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My thinking is that combis are not quite ready for Times Square. They are popular in Japan and Europe where many people live in couped-up apartments and have limited mechanical DIY skills. When their Toto toilet acts up, they have to call a factory technician wearing a Toto-logoized shirt. DIY? Hmm.
 
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Old 11-20-12, 06:40 PM
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Since the guy supplying the parts is cheap I did what I could.

I put a valve on the return so I can isolate the system there, along with the purge valves. If parts need service the boiler will need to be drained.

It don't hold that much water. And when you fill it purges right out from the built in air vent.

I have since changed those red ball valve type boiler drains. The guy likes them and I think they suck.. Tap them by accident and you get wet...LOL

I put regular washer type drains in their place.

The whole pipe connection bar under the boiler is all unions.
 

Last edited by lawrosa; 11-20-12 at 08:15 PM.
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Old 11-20-12, 08:13 PM
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Yes that ugly guy is me
OUTSTANDING BEARD! Reminds me of when I was a young feller like you! Now it's all gray and only half as long, but I've retained the cheek warmers.

Tap them by accident and you get wet
I heard that! (hint: brass caps!)

NICE JOB!
 
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Old 11-20-12, 08:30 PM
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I cant locate one of these locally. Anyone? Its for the LWCO. I dont want to drill a hole in a cover plate.

Not even sure thats allowed. The transformer I was given has leads also.

http://www.plumbingstore.com/images/...ransformer.jpg
 
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Old 11-21-12, 03:10 AM
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Uponor has a 50VA version.
A3050050 - Uponor (Wirsbo) A3050050 - 50 VA Transformer
There are also others that screw into the knock-out on an electrical box, the 120 vac leads then can terminate inside the metal box.
Honeywell makes these I think.

This may work as well
Honeywell 24-Volt Transformer AT72D at The Home Depot
Not as convient,
Amazon.com: Honeywell AT72D1006 Transformer, plate mount, 24 volt 40VA, 115 volt primary 4" x 4" box mount: Home Improvement
 
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Old 11-21-12, 06:23 AM
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You should be able to buy a cover plate like that from the local bix box, I think. I have one installed for my boiler. I think my guy got it from Lowes.

EDIT: Found it at Home Depot: 2-Gang 4-11/16 in. Square Cover (50-Pack)-833 at The Home Depot

Maybe you mean the transformer?
 
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Old 11-21-12, 06:37 AM
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Yes the transformer that is already mounter to the plate I am looking for.
 
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Old 11-21-12, 10:49 AM
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Old 11-21-12, 11:03 AM
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Based on the photo, how in the world is a man supposed to work on that thing?
 
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Old 11-21-12, 04:54 PM
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Well I got the cover plate from depot with the knockout. Then drilled two holes and pop rivet the transformer to the plate.

All done and here is the finals. Sorry pics are from my crappy phone.

Front view. All BX and wires were secured to the wall and or wire tied. ( That was last thing....Uggg)

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Piping

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Zones. Only thing I did wrong here is kept the original bleed stations. They are above the zone valves. Should of moved then.

I was more focused on keeping the zone valve close to the 403 so I could wire right to it. As well as the transformer for the LWCO.

( Note: Make sure hose is tight when bleeding....LOL. How do I know...ha ha)

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Well This was my first combi boiler and feel I did a good job.
Total hours was about 20 over the course of 4 days. Guy paid me 1K


So anything you see wrong let me know. I have time to fix since the inspectors are backlogged.


Oh operation was strange.

Call for heat and the boiler would run and system circulator would run as would seem normal . But then zone would still be calling and the system circ would stop. The boiler would continue to fire ,then ramp up temp to about the 140 mark or so, and the system circ would start again.

Like it would get hot, then feed the system, get hot then feed the system...etc.

Oh HW was very good, constant.


But I would hate for something electronic to go wrong with this unit. Looks cool but not for me.
 
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Old 11-21-12, 05:12 PM
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Call for heat and the boiler would run and system circulator would run as would seem normal . But then zone would still be calling and the system circ would stop. The boiler would continue to fire ,then ramp up temp to about the 140 mark or so, and the system circ would start again.

Like it would get hot, then feed the system, get hot then feed the system...etc.
Haven't spent much time with the manual other than to criticize it... (sorry!)... but I suppose this could be normal operation?

Did it seem as though the pump would cut back in at the same temp after being off ?

Is there any way to query the boiler to determine what the boiler temp setpoint was at the time?

It sounds as if it may have been 'bouncing off' that setpoint limit.

So anything you see wrong let me know. I have time to fix since the inspectors are backlogged.
Looks good! ... oh, damnit, I can't help myself from nit picking and busting chops... please forgive me...

That transformer box is a bit caddy wompus... I need to call the inspector and tell him to be on the lookout for that! BAHHH HAAAA HAAA HAAA ...

Seriously man, beers on me if we ever get together at Tom's.
 
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Old 11-21-12, 05:32 PM
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Since I cant quote,

No troop is was a vaied temp when the circ kicked on. 144f, 150 f, 146f...etc

I did not sit there to go through the manual. Its running on auto with ODR. System temp was runninng at 100f or so mid day and later when temp dropped to 48 outside it seamed to increase. 117f or so.

Just ran it enough to make sure it was running off ODR and not running high fire.

Going back friday just to check operation.

Toms this week end. Sunday? Noon?
 
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Old 11-21-12, 05:48 PM
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Since I cant quote,
Why can't you?

vaied temp when the circ kicked on. 144f, 150 f, 146f.
But within a few degrees anyway... I'm thinking normal... TOHeat seems to have a better grasp on these and I'm sure he'll be by soon to help us understand!

Toms this week end. Sunday? Noon?
Long as the Admiral gives me a shore pass should be good to go... I've been good, she probly will.
 
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Old 11-21-12, 07:16 PM
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I'll read though the manual when I get a chance.
I think that x-former is not needed. The ZVC box has at least 40VA built into it, enough to run 3 zone valves. What exactly are you using the x-former for anyways.

These boilers sometimes have delta T limits.
So if you coming from a cold start, you can easily excede the delta T limit in the control and it might drop the circ to help protect the boiler.

Not 100% sure in this case, but I know from experience with a TT, a large cold in floor slab keep the boiler on low fire for hours while the water temp came up.
 

Last edited by TOHeating; 11-21-12 at 07:32 PM.
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Old 11-21-12, 07:27 PM
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The transformer was for the gaurd dog LWCO. There was a port for it in the combi but i ran it external so the inspectors will see it.

It just breaks the end switch so the boiler dont fire. ( well how I wired it anyway. ) There was probably a way to wire in the boiler electronics but I really wanted to stay out of there.

The menu for this system IMO is confusing and the manual is even more confusing.

Although I spent most my time reading the piping diagrams then the parameter adjustments and opted for the auto setting.

Not really my problem now. Not my job. I was only the installer. They got heat and hot water. If the guy that sold the job wants to tweak it then he can.

Well next boiler I believe monday is a Burnham ES2. I have questions on that. Like should I do boiler by pass no matter what???
 
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Old 11-21-12, 07:32 PM
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Just a FYI, you can get 24vac out of a taco ZVC or SR box easily.
Around here they like to see stand alone LWCO also, they want us to wire them in sure a way so the boiler cannot fire no matter what.
 
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Old 11-21-12, 07:35 PM
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How do I get 24 volt out of the 403 I used?

I was thinking to myself there could be, but I already had the transformer and did what I know.
 
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Old 11-21-12, 07:38 PM
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After reading a bit, I found this statement.
 The boiler will shut down when the target temperature is reached followed by a 3 minute post purge by the pump unless the 3rd party room thermostat is satisfied prior.

Does this sound like what is happening ?
 
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Old 11-21-12, 07:41 PM
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The easiest way is to just take it from where it enters the terminal strip on the PC board.
R is also on the thermostat terminal strip, and C is on the zone valve terminal strip, but that is not as easy as just taking it from the transformer as it attaches to the PC Board.

The newer ones now tell you where R and C are
 
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Old 11-21-12, 07:44 PM
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No. system pump will shut down. Taco 403 will show zone and t stat still calling.

Boiler will do nothing for some time and no pump running.

I believe what I saw was the boiler raising its temp to a certain point and then the system pump would kick on again.

But only for a short time the system pump would run. Then a repeat of the above.

I will read some more when I have time.
 
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Old 11-21-12, 08:02 PM
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Did you wire the system pump to the ZVC403, or the boiler ?
The boiler pump is built into the unit right ?
 
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Old 11-21-12, 09:29 PM
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I wired the system pump to the combi....

Boiler pump is built in yes...
 
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Old 11-22-12, 09:44 AM
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The newer ones now tell you where R and C are
In fact, many of the newer ones that I've seen have a dedicated terminal block for the 24V.

Happy Thanksgiving everyone!
 
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Old 11-22-12, 10:16 AM
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Got a call this morning , no heat...LOL.

Manual stinks period !!!!! German engineering...LOL.

I had set to auto which runs a preset program that goes into night setback and or some defrost mode/ economy setting.

Page 27 here Switched it from auto to comfort setting, which is the sun icon..

http://www.bosch-climate.us/files/20..._FW200-ISM.pdf

All seems to be working now. I really dont understand the point of that dial......




Anyhoo the Swanson turkey TV dinners are in the oven....Ummmmm.... Cant wait!!!!
 
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Old 11-22-12, 11:12 AM
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Manual stinks period !!!!! German engineering...LOL.
Same as the manuals for Stihl (German) weed wackers and chain saws. Stihl tries to explain everything with goofy drawings and no words. Give me good old Japanese manuals any day.
 
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Old 11-22-12, 02:05 PM
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Taco old stock????

IDK looking at docs online I see all the staus lights on the right side in a strip. The 403 I got have them on the front.... Huh????

http://www.doityourself.com/forum/at...icture-037.jpg

I assume I could just tap off for 24v for the LWCO at the oposite side of the terminals in the 403???

Where those yellow wires attach to the transformer in the first page here... Left pic. I believe thats a 404.


http://www.taco-hvac.com/uploads/Fil...ry/100-5.1.pdf
 
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