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  1. #1
    rubobornot Guest
    I am currently working on a Lochinvar water heating system,
    model # CWN0745 S#L951036. The problem has come down to the fintube coil restricted on the outside causing the burner to lockout. The diff. pressure of the comb. air is 3.5 iwc. , the inlet gas is 6.5 iwc. , manifold 4 iwc. on both manifolds and the draft pressure is -.01 iwc. According to the man. the draft should be between -.01 and
    -.08 iwc. Talked to the factory rep. and he said to clean the coil in place and install a draft inducer with a
    baremeteric damper. He also said that the min. return temp. for the heater section should be 140 deg f. to prevent
    condensing . They want to run the supply temp. at 104 to prevent scalding from hand sinks in the day care area. has anybody used a heat exchanger with a 3 way valve between the heater and storage tank on an application like this ?
    Thanks for the input Bob.

  2. #2
    Join Date
    May 2004
    Posts
    91
    "He also said that the min. return temp. for the heater section should be 140 deg f. to prevent
    condensing . They want to run the supply temp. at 104 to prevent scalding from hand sinks in the day care area. has anybody used a heat exchanger with a 3 way valve between the heater and storage tank on an application like this ? "

    This is a sure fire way to rot out a boiler... Run a storage tank (like a Superstor) and mixing valve... the boiler will like it and you will gain capacity. I would clean the fin/tube boiler and check operation before adding and inducer... are there problems with poor draft or is the factory taking a shotgun approach?

  3. #3
    Join Date
    Nov 2003
    Location
    vermont
    Posts
    48
    lochinvar I feel sorry for you I used to work on some, they were direct vent and they were strictly domestic waterheaters. maybe yours not the same. It sounds like it well start and fire then shuts off. Ours had the same problem but it was always flame sensor problem. we had ours coupled with 600 gal storage tank with constant circulation, with 2" mixing valves to keep it at 120 deg. I think that would be your best bet to have lowet temp. could have smaller storage tank with mix valve. good luck

  4. #4
    Join Date
    Oct 2002
    Posts
    970
    lochinvar boilers are garbage IMO..just thought I'd throw that out there.
    I work with the Chiller Whisperer...

  5. #5
    Join Date
    Feb 2003
    Location
    Wichita Ks
    Posts
    1,457
    if you install a 3way valve, remember the water heater needs full flow so dont install the 3way valve to restrict the water flow to heater. i would install temperature mixing valves where needed and set the boiler at 140. the mixing valve leaving the storage tank can be set where you want it.

  6. #6
    Join Date
    Dec 2001
    Location
    Southern Tier, NY
    Posts
    6,066

    loch's !

    boilers made outta sheetmetal and red RTV

  7. #7
    I'm with sonc and slim.....JUNK!!!!

  8. #8
    Join Date
    Feb 2004
    Posts
    534
    I do alot of nursing home work, I found using a hot water storage tank and then mixing the supply with a holby mixing valve seems to work fine you should have no trouble.

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