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Old Hydronic System

Ray Landry
Ray Landry Member Posts: 203
Using water heaters as boilers is wrong for a few reasons. 1) The recovery isn't as quick as a normal boiler (Which explains why you're having trouble heating your place on cold days, if your bringing back cold return temps the thing just can't keep up with the demand) 2)Its not legal in some states. (It even says right on the water heater not legal for space heating in some locations. 3)It probably won't even last 5 years with the demand your putting on it. The only application that a water heater has as a heating boiler is on low temp radiant. And even then I myself don't think itas a good idea.

There could be a great number of piping, wiring, and control issues with this system. You really need to get us a picture or a piping diagram, either that or we'll just be picking needles out of a hay stack.

BTW the pump position is only relative to the EXPANSION TANK not the boiler.... so moving your pump so that its pumping away from the tank is your best bet.

Comments

  • Monty Betts
    Monty Betts Member Posts: 4
    Old Hydronic System

    I have an old hydronic system in my building. The boiler went bad and my supplier recommended replacing the boiler with a water heater. My building is approximately 2,000 sq. ft. with a 10 ft. overhead door. I installed the water heater and it seems to be sufficient until the outdoor temperature reaches the single digits. When dealing with single digit temps it runs forever trying to keep up with the heat loss.
    What really has me puzzled it how the pump is set up on the old system. There are 4 zones, ranging in pipe size of 1" to 1 1/2". The pump is pumping from the zones into the heater. The supply side of the heater actually pumps into the return piping. The only way I have to balance the zones is with old gate valves that are installed in the old piping. I'm a little concerned with trying to manipulate these valves. We all know what can happen with an old gate valve.
    My question is: Should I reverse the direction of the pump and pump through the supply manifold or will it really make any difference. The pump is an H-2 Bell and Gossett. Currently I believe all the gate valves are in the full open position. BTW the water heater is a 75 gal. 75,100 BTU input.
    I know I've probably left out some details but I'd sure appreciate any advice anyone would be willing to extend.
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,594
    Have you spoken

    to your supplier, the guy who recommended the water heater?
    Retired and loving it.
  • Monty Betts
    Monty Betts Member Posts: 4


    I have, he contends that the water heater should keep up with the demand, but he has no clue as to whether the pump direction should be changed or not.
  • kevin coppinger_4
    kevin coppinger_4 Member Posts: 2,124
    was there...

    a heat loss done? What are the size of the manifold pipes? I s the circ sized properly? kpc

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  • Steve Ebels
    Steve Ebels Member Posts: 904
    Is this

    Is this a standard configuration water heater? What I'm refering to is the location and position of the supply and return pipes you are describing. Both on top?

    Also do you have any way of seeing what the actual temp of the supply water is? Most residential water heaters will not go much above 140*.

    Here in Michigan, it is illegal to use a water heater for space heating purposes. The are neither tested nor approved for that use. Using one that way voids the manufacturers warranty. (Just call them up and ask, see waht response you get)
  • Monty Betts
    Monty Betts Member Posts: 4


    This is a regular water heater, top connections. The supply temp is 155 F. After the heater has exhausted it's supply of hot water the temps on supply and return even out to approx. 95 F. I know that this should void the warranty of the heater. In fact I brought that objection up to my supplier. His response, " Hey we're the only ones who know what this heater is being used for and therefor that's not an issue." Sound like a stand up guy to you? I'm beginning more and more not to think so.
  • flange
    flange Member Posts: 153


    find yourself a good reputable local guy, call him out and have him take a look. my guess is that you are buying a new boiler soon, but you never know. i bet someone around here would be willing to help you out.
  • Monty Betts
    Monty Betts Member Posts: 4


    Actually I need to retract part of my last posting. After checking the label on the heater I've found that it says that it is suitable for space heating.
This discussion has been closed.