Boiler settings question/problem

Discussion in 'Boiler Forum' started by MrSabre, Feb 2, 2013.

  1. MrSabre

    MrSabre New Member

    Messages:
    1
    Location:
    London, ON
    Hello everyone, very glad I found these forums.

    I have just bought a building which has 2 Olsen OMGB-250 gas boilers, with a Tekmar 264 control. The control unit has a lot of settings which are confusing even after reading through the manual. Calling the company that installed it didn't help, they didn't even show up. Anyhow, from what I can see these are the current settings:
    Room temp occupied - 72 F
    Design temperature - 140 F
    Outdoor design temp - 0 F
    Terminal unit - 4 (fin-tube convectors)

    Mode - 1
    I think this might be a problem since the manual states the following:
    Mode 1: 4 Single stage boilers and a primary pump.
    Mode 2: 2 Single stage boilers with individual boiler pumps and a primary pump.
    Mode 3: 2 Lo / Hi boilers and a primary pump.
    Mode 4: 1 Three stage boiler with a boiler pump and a primary pump.

    The design of my unit is not even listed because I have 2 boilers (no idea how many stages) each with their own small pump, but only the first boiler has a primary pump. The second boiler's individual pump is directly attached to the hot water pipe AFTER the primary pump. Also, I have a separate boiler for DHW which is not connected in any way to this system.

    Recently the temperature in one of the apartments was 55 F which is unacceptable. So I went to check the boiler temps and I found that the supply temperature target was 134 F but the current temperature of the water was only 120 F. So I increased the Design temperature to 160 F and the target was changed to 145 F, but even after a warm spell outside and checking the temperatures every day I found that the supply temperature would never rise above 121 F. I also noticed that even though the control unit says boiler 2 was on the whole time, it actually only turns on for a couple of minutes at a time. (I read another thread with the same problem that said this could indicate an air bubble or a failed pump. All pumps are working and I have bled the fin tube convectors in all 47 units and the outcome is still the same.)

    Tekmar 264 manual: www.tekmarcontrols.com/images/_literature/264_d_06.pdf
    Boiler manual (not very helpful with max temp settings, although does state that the boiler itself also has a control for high temps): http://www.ecrinternational.com/secure/upload/document/2427.pdf

    Any help would be greatly appreciated.
    Last edited: Feb 2, 2013
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