PLEASE HLP! 2 zone heating funtioning on 1 zone only


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Old 10-18-09, 06:45 PM
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Smile PLEASE HLP! 2 zone heating funtioning on 1 zone only

We have 2 thermostats (upstairs and downstairs). However, when you turn on the upstairs thermostat, the downstairs heat also turns on. When we turn on the downstairs thermostat you can hear a "clicking" sound but the furnace does not turn on. The piping on the 2 zones are good.

Does this mean that the Zone Valve needs to be replaced?

The downstairs thermastat replaced? (Im thinking its not this because the upstairs thermostat shouldnt be turning on the downstairs heat regardless)

Ive also heard that sometimes is just the Zone Valve motor, is there a way to test if this is the case?

Any help would be greatly appreciated
Thanks in advance!
 
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Old 10-18-09, 06:55 PM
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First of all, I would check the wiring of the system. Start by tracing out the wires from the thermostats to the zone valves. Be sure that each thermostat is wired to only one zone valve. If possible, also determine which thermostat connects to which zone valve, then try to trace the piping and verify that the piping goes to the correct area. It may be as simple as something not being wired up correctly.
 
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Old 10-18-09, 07:09 PM
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You didnt mention if it has always been like this (for you... as in, you just bought the place etc).. or did it work fine last year and now has this trouble.

A zone valve should have either 3 or 4 wires going to it. There's 2 distinct circuits .. the motor drive (gets its 24v a/c from the thermostat switch 'on' command), and the end switch (turns 'on' once the motor drive opens the valve). The end switch controls a relay (sometimes outboard, sometimes in the aquastat/furnace control itself) that turns on a circ pump and/or turns on the boiler. A 3-wire zone valve design just shares a power line.. same deal otherwise.

That both zones get heat shows that both valve are open (so the downstairs valve is either stuck open mechanically, or it's continuously on a call for heat (but the end switch isnt turning on the circ/boiler on its own)..
 
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Old 10-18-09, 07:15 PM
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We just bought the house. Its fairly old 1965, but the furnace and the piping is brand new. This is the first time we've used the heat.

I will check the wiring... It might be easiest if I posted some images to give you guys a good look. Gimme an hour and Ill have them posted.

You said that the valve gets its 24v from the thermostat. Is is possible that replacing the thermostat might be the way to go? It look really old.

Thanks guys. Sorry Im a newb to this stuff.
 
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Old 10-18-09, 07:23 PM
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Yeah, pics...

Until you said that the system is brand new, I was thinking that maybe the previous owner had a bad valve, and manually opened it, and buggered the wiring to just run on one t'stat...

but since you said it's brandy new, I'm with the other guys that it's got wiring errors, and was never running properly.

Yeah, let's see the pics.
 
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Old 10-18-09, 07:56 PM
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Picasa Web Albums - drharney - 2009-10-18

Let me know if I should take pictures of anything else!
 
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Old 10-18-09, 08:12 PM
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Doc, from what I can see in the pics, the downstairs zone is not set up to fire the boiler, only to run the circulator pump (which is what that black thing is that you don't know what it is).

I assume the upstairs thermostat wires into the other gray box on the front of the boiler, and the other black circulator pump is wired there also, correct?
 
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Old 10-18-09, 08:13 PM
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I will defer to the wiring gurus on what will make it go.

However, on first look it appears that the downstairs zone is pumping in series with the upstairs. That's not how it should be, and once the probable wiring error is fixed, there might be other problems. There should be a common header.

And the oil line should not be lying open on the floor.

You have circulators (one for each zone), so don't have zone valves.

Let's see a couple more pictures of the rest of the piping above the boiler where stuff takes off to the different zones, the air eliminator, expansion tank, etc.
 
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Old 10-18-09, 08:16 PM
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"I assume the upstairs thermostat wires into the other gray box on the front of the boiler, and the other black circulator pump is wired there also, correct?"

Exactly right


"Doc, from what I can see in the pics, the downstairs zone is not set up to fire the boiler, only to run the circulator pump (which is what that black thing is that you don't know what it is)"

Is this normal? What good is only running a circulator pump? How difficult would it be to set it up to fire the boiler? What is entailed so that I can tell a contractor to get price estimates
 
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Old 10-18-09, 08:21 PM
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Let's figure the whole thing out. Early impression here is "hack job." More than just wiring will probably need to be corrected.

And what's up with the face plate of the tankless coil? Why can I see insulation behind it, in front of the boiler jacket?
 
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Old 10-18-09, 08:22 PM
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It's doubtful to me that a 'pro' installed this... probably the previous homeowner as a DIY, or maybe his brother-in-law...

I don't think you have zone valves. None seen in the pics (though the pics don't show everything), and the fact that you have two circulator pumps is further evidence that you don't.

You see, you can zone a system with Valves, OR with Pumps.

Yours is zoned with pumps.

The reason you get heat downstairs when the upstairs calls is probably because there are no 'check valves' installed. Without the proper check valves, when one pump runs, it will pull hot water through the other zone in the opposite direction.

And, we already know from looking at the pictures that the downstairs thermostat is only wired to the pump, and not to fire the boiler.

In order to fix this, you would need a 'switching relay', some rewiring, and check valves installed.

They do make pumps with built-in check valves, and you could replace those pumps with that type. Or, a separate check valve could be installed in the piping.

Can we see the rest of the system please?
 
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Old 10-18-09, 08:30 PM
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Yeah, I just looked at the return piping again Xiphias, and that is all whack... that needs to be redone.

DrHarney, you might have a case with an insurance company on this... it's worth a shot.

I would recommend that rather than listen to us, you get a written estimate from a reputable heating contractor as to what it will take to fix it up, you might need the documentation for a claim.

What we can see in the pictures though, all that piping around the oil burner needs to be re-done, and you will need some electrical controls (the switching relay) to run the pumps, and to fire the boiler up.

There may be more that needs done once we see the rest of it.

Was there a home inspector involved? Any warranty on the inspection?
 
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Old 10-18-09, 08:33 PM
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Picasa Web Albums - drharney - 2009-10-18

3 new pictures added
There's not much up there

The previous owner is a contractor that was probably trying to get the job done as cheap as possible. UGH.


"And what's up with the face plate of the tankless coil? Why can I see insulation behind it, in front of the boiler jacket?"

It supposedly a new furnace. That's not normal?
 
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Old 10-18-09, 08:38 PM
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Originally Posted by NJ Trooper View Post
I would recommend that rather than listen to us, you get a written estimate from a reputable heating contractor as to what it will take to fix it up, you might need the documentation for a claim.

Was there a home inspector involved? Any warranty on the inspection?
Do you mean home insurance claim?

Also, there was a home inspector and he completely missed this.

Is there anything you guys would see as dangerous before I get to contact a contractor?
 
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Old 10-18-09, 08:40 PM
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Definitely a hack job... they reused that antique switching relay (which I would have too, but I'm a hack), and no commercial installer would have done that... further, the armored cable going into the bottom of the box has no 'anti-short' bushings on it, and they appear to be the wrong kind of connectors... they look like regular NM cable connectors. Even a 'hack professional' would do a better job terminating those wires.

It also tells me that there was no inspection by the building department of this install, cuz they would have immediately flagged the missing anti-shorts, and the wrong connectors.
 
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Old 10-18-09, 08:44 PM
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Originally Posted by drharney View Post
Do you mean home insurance claim?

Also, there was a home inspector and he completely missed this.

Is there anything you guys would see as dangerous before I get to contact a contractor?
I dunno if your homeowners insurance would cover it, but what about a Warranty ?

You should really hold the inspectors feet to the fire. He missed it and should be accountable, and he was YOUR inspector, right?

I don't see anything particularly unsafe about anything in the short term...
 
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Old 10-18-09, 08:47 PM
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I don't think it's normal for the tankless coil assembly to be sticking out of the boiler jacket. What's the make/model of the boiler?

Please read the markings on the orange tubing and report them. I think it's oxygen barrier PEX by Watts, but not sure.

Your flow checks are the green gizmos on the supply side piping where the black painted piping ends. The expansion tank is the big gray canister. The air elimination device is the gizmo above it.

Good news is there's plenty of room to repipe, hacking out pex is easier than copper, and you can do a standard header with the circulators on the supply right downstream of the expansion tank. Then do a proper return header on the return to the boiler.

And add the switching relay you'll need to make the circulators run when they're supposed to, and the boiler to fire when it's supposed to.

Bad news is you're redoing a hack job. Bummer.
 
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Old 10-18-09, 08:49 PM
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Those green things near the ceiling are check valves... but they may not be able to do the job they need to do with the return piping the way that it is.
 
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Old 10-18-09, 08:56 PM
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I think I see the fill water on the back right (a lighter blue pex than the domestic), but I don't see a pressure relief anywhere.

More pics from the right side, please.
 
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Old 10-18-09, 09:19 PM
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OKAY 3 more pictures of the right side guys. Thank you so much for your help. Really appreciate it.

Please read the markings on the orange tubing and report them. I think it's oxygen barrier PEX by Watts, but not sure.

PDR-9 100psi 180 degrees

Good news is there's plenty of room to repipe, hacking out pex is easier than copper, and you can do a standard header with the circulators on the supply right downstream of the expansion tank. Then do a proper return header on the return to the boiler.

Hey, at least something went my way Will they need to replace the check valves? Are they too far away from where there supposed to be?

hacking out pex is easier than copper, and you can do a standard header

What is the function of a header? Also, Will they need to remove the circulator pumps to get this to work?


Thanks guys
 
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Old 10-18-09, 10:22 PM
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The only thing that is an immediate problem is the pump attached directly to the boiler. Once it is moved to the copper piping above the valve the system will function. I'd hold off on the removal of the PEX, building of headers, rewiring and all until next summer.

The switching relay is fine. Since this boiler has a tankless coil the aquastat will fire the burner anytime the boiler temperature drops to the cut-in temperature. It is not necessary for the switching relay to fire the burner.

Look on the back side for the safety valve.
 
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Old 10-19-09, 06:59 AM
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Originally Posted by furd View Post
The only thing that is an immediate problem is the pump attached directly to the boiler. Once it is moved to the copper piping above the valve the system will function. I'd hold off on the removal of the PEX, building of headers, rewiring and all until next summer.
Very good point.

But if it's already getting opened up (and I'm still wondering why the tankless coil doesn't look like it's installed correctly into the boiler; and where is the pressure relief? he's got the backflow piped right, so that's encouraging...), there might be an economy of scale to just pull it apart and get it all set up right. Small, practical, headers could be built as modules before taking the system apart.

Yes, you can reuse the flow-checks, and the circulators.

There ought to be more markings on the pex. sdr-9 is just a size rating.

What make/model is this boiler?
 
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Old 10-19-09, 07:25 AM
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Originally Posted by furd View Post
The only thing that is an immediate problem is the pump attached directly to the boiler. Once it is moved to the copper piping above the valve the system will function. I'd hold off on the removal of the PEX, building of headers, rewiring and all until next summer.
First, Thank you all very much (xiphias, nj trooper, furd)

We have a contractor coming in to take a look. We plan on getting the whole system redone after a bit of saving next summer... but hope to get it in working order for this winter.

Which pump needs to be moved? The one which is directly attached the boiler, or the one which is sandwiched between the two valves on the vertical copper pipe? If this pump is moved will the downstairs thermostat (barring any other problems) be able to fire the boiler?

From the look of the manufacturer's site.. The pump attached directly to the boiler is there by default. Take a look-

S SERIES

Originally Posted by furd View Post
Look on the back side for the safety valve.
Found it. Good call, Theres a release valve and some PEX pointing down

Originally Posted by xiphias View Post
What make/model is this boiler?
S SERIES

Its a Thermo Dynamics Boiler Company S series S-110
 
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Old 10-19-09, 10:20 AM
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The pump directly attached to the boiler needs to be moved to the vertical copper pipe above the valve. Both pumps will then have their discharge piped to the boiler.

Understand this is not the ideal, to do it properly both pumps should be re-mounted to a supply manifold where they would then pump to the Flo-check valves and then to the system. The expansion tank should be on the suction side of the circulation pumps.

If the PEX piping is relatively short it most likely was installed when the new boiler was installed just because it is cheaper and faster than using copper. It is not a big item IF they used a proper oxygen-barrier tubing but it looks cheap in my opinion. I would replace it with copper.

The downstairs thermostat can fire the boiler as long as the switching relay properly operates the circulator pump on the downstairs circuit. The burner is controlled by the temperature of the boiler water and will fire regardless of whether either circulator pump is running AFTER the pumps are properly plumbed.

Xiphias, the domestic coil is fine. This boiler manufacturer uses an external flange to eliminate the problem of broken studs or castings when replacing the tankless coil. From the website:
Extended Flange Coil is away from the boiler for easy accessibility. The use of ribbed neck carriage bolts eliminates the problems encountered when a weld stud is broken during servicing. The large coil plate allows for a greater gasket sealing area.
 
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Old 10-19-09, 10:32 AM
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Well that's interesting. Never seen one of these before. Looks like the coil is supposed to be sticking out and thus the insulation visible. That's a 'service feature', apparently.

Figure 3 shows how the boiler is to be piped, but that's one of the oddest ways I've ever seen to do it.

I see that furd now has a comprehensive reply so I'll stop here.
 
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Old 10-19-09, 10:49 AM
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Nothing really wrong with that figure 3 drawing other than poor labeling of the various pipes and it giving the assumption that all the pipes are the same size. It has a tempering valve in the domestic hot water circuit and also shows an untempered branch that would run directly to a dishwasher although the dishwasher comment is not to be found.

Of course it does have the grievous fault of having the circulator pump on the wrong side of the system.
 
 

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