Improving performance of my tankless coil

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  #1  
Old 01-31-08, 03:37 PM
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Improving performance of my tankless coil

Short of replacement (which I don't want to risk damage to the boiler by snapping a stud) what can I do to improve the performance of my tankless coil?

I've got to crank the heat in order to get enough hot water for a hot shower. My coil is supposedly 5 gpm but in order to fill a tub I have to dial the water back to about 50% of full flow.

Thanks.

Jeff
 
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Old 01-31-08, 04:32 PM
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Jeff, this option worked well for me. I was also afraid I'd ruin the boiler if I tried to take the bolts out. I converted the tankless coil HW in my old (1975) American Standard oil fired boiler to a variation on indirect HW (with help from a friend who used do plumbing for a living). Reason was the coil wasn't producing HW rapidly enough, probably due to scale reducing heat transfer. I was going to put a new one in and was advised that some of the bolts were pretty rusted and it has happened that the boiler is damaged when trying to remove the old coil. The solution, although more expensive, was to add an insulated HW tank w/ a thermostatically controlled circulator that runs through the tankless coil. So I basically have a 40 gallon HW 'capacitor' which gives me enough HW. After reading about indirects, my set up sounded like essentially the same thing, although no doubt not as efficient. See photos of set up:
http://i169.photobucket.com/albums/u...A/DSCN1091.jpg
http://i169.photobucket.com/albums/u...A/DSCN1090.jpg
http://i169.photobucket.com/albums/u...A/DSCN1089.jpg
 
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Old 06-21-08, 06:04 PM
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Mike C5

Hey Mike new to this site but I will like to add the same setup as you have, Do you have some more pic? if so please post ...

Also which side to you have to HW entering your Hot water tank?
 
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Old 06-23-08, 10:24 AM
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I'll post some more info tonight.
 
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Old 06-23-08, 04:05 PM
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Looking forward for the PIc
 
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Old 06-23-08, 07:13 PM
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OH,

I annotated a few of the images and added a photo of the pipe/wiring schematic. This set up was more expensive than replacing the tankless coil assuming the boiler wasn't ruined in the process... But we are much happier with 40 gallons of ready hot water....

http://i169.photobucket.com/albums/u...A/DSCN0547.jpg
http://i169.photobucket.com/albums/u.../DSCN1091m.jpg
http://i169.photobucket.com/albums/u.../DSCN1090m.jpg
http://i169.photobucket.com/albums/u.../DSCN1089M.jpg
 
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Old 06-23-08, 07:34 PM
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Thanks mans, I think I understand now, but here is my problem.. I had the same setup as you a month ago with my old boiler now that I replaced my old boiler which had a tankless coil with a new a boiler with tankless coil . The hot water pressure on my top floor is low now trying to figure out the problem, do not know if the guys that install the boiler did not understand the setup I had before, and came across your setup which look also like mines... Question is on the EHWT there is 2 inlet 1 is for HW and the other for cold water.. Can i add some PICs of my setup?
 
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Old 06-23-08, 08:18 PM
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Pics

The easiest way for us to be able to see your pics is for you to post them on photobucket.com (free) or similar photo hosting site. Then you can provide a link to those pics here.
 
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Old 06-23-08, 08:48 PM
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Old 06-23-08, 09:17 PM
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Piping?

That piping arrangement makes so sense at all to me. How about some wider shots including the boiler.
 
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Old 06-24-08, 06:51 AM
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You're welcome. The tank should have 3 ports, the two on top and one at the bottom (the combo fitting in my set up).
 
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Old 06-24-08, 04:02 PM
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Grady, here's a link to the full album (8 photos) but I don't think it's gonna help much...

Problem is with pics that it's difficult to 'follow the pipes' from one shot to the next, and when the shot is far enough away to see all the pipes, they're too small to see !

Yeah, that's the dadgummest thing I ever saw !

Overthehill's full album
 

Last edited by NJT; 06-24-08 at 08:27 PM.
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Old 06-24-08, 08:24 PM
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Mike isnt the port on the bottom on the tank is for draining out the water...?
 
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Old 06-25-08, 05:51 AM
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Yes it has a valve and is threaded to accept garden hose but it also serves to feed cooler water in the bottom of the tank back through the tankless heater. I believe that's why they call it a combination fitting.
 
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Old 06-25-08, 11:21 AM
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Everyone I know the pic are kind of confusing,

But watching the Tank pic from in front, the pipe on the left side back pipe where the circulator is installed connected to that is my Hot water going to the APT the front left pipe with the valve that pipe is bringing the HT to the tank and the pipe on the right side that pipe is feeding CW in the tank... Hope some one under stands now.. The problem is that my hot water pressure is very low on my top floor..
 
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Old 06-25-08, 12:05 PM
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I'm not going to pretend I have the remotest idea of how that mass of spaghetti works but I do see one thing that bothers me. It appears that the draft regulator on the boiler smokestack is tilted downward. If so then that needs to be realigned so that it is horizontal and then the draft checked.

As for the "pressure" problem...are you perhaps confusing pressure and flow?
 
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Old 06-25-08, 12:17 PM
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i think it is Pressure not flow
 
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Old 06-25-08, 12:27 PM
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Does your cold water have the same apparent pressure as the hot? If you fill a bucket does it fill at the same rate using either the hot only or the cold only?

How high is your top floor above the basement? Do you have galvanized piping to your top floor? Do you have any means to connect a pressure gauge either on the top floor or in the boiler room to the domestic water?

What does APT in the following statement mean?

But watching the Tank pic from in front, the pipe on the left side back pipe where the circulator is installed connected to that is my Hot water going to the APT the front left pipe with the valve that pipe is bringing the HT to the tank and the pipe on the right side that pipe is feeding CW in the tank.
Is there any way that you can post a picture from a ways back or using a wider angle lens setting so that I (we) can see how all the piping connects AND can you add some tags showing the source (supply) cold water and the hot water supply pipes?
 
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Old 06-25-08, 04:35 PM
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APT mean (rental Apartment) Cold water is fine on top floor but is just the hot, my to floor is from my basement is about 2 story high 10feet each... no galvanized piping here I will try to post some pic?
 
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Old 06-27-08, 08:16 PM
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Hey just added some new photos.. could take a look,.
 
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