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Thread: Zone 3 barely working

  1. #1

    Default Zone 3 barely working

    Hi Terry,
    I bought a house last year with an hydronic system (I've never owned one before so this is a learning curve although I am fairly handy until things get too complicated) consisting of a Dettson boiler with 3 zones. The house is a bungalow with the basement as one zone and the upstairs zones 2 (all the bedrooms) & zone 3 (livingroom, dining room and kitchen). Zones 1 & 2 work fine. Zone 3 has 5 baseboard rads (they look like electric baseboards but have the copper pipe runnning through) and is the farthest from the boiler. The first rad in this zone (from the boiler) gets almost hot (extemely warm?) and then the other 4 get progressively cooler even when we set the thrmostat to 25 or 30 C. My boiler is running around 15 psi when heating. I thought it might be air, so I put a self piercing saddle valve in the 4th rad (2 rads away from the return) and bled the line but it didn't really need to be bled. I was going to try and flush the zone but didn't know how. The only valve I could see is a bell shaped fitting in the water entry pipe. Any suggestions?
    cheers,
    Kim

  2. #2
    Master Plumber nhmaster's Avatar
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    Default

    Air in the system would be my first guess and the saddle valve was a bad idea. The air needs to be purged at the boiler. There should be a purge valve somewere near it. Second choice would be a bad circulator. If you have zone valves and one went bad you would have no heat in that pipe at all. Third choice is all electrical. Either thermostat or zone control relay.

  3. #3
    Moderator & Master Plumber hj's Avatar
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    Default air

    If it is air in the system it would be almost anywhere EXCEPT the spot where you inadvisably installed the saddle valve. The ENTIRE zone has to be purged of air, but without seeing your system we cannot tell you how it was arranged to do that.

  4. #4

    Default

    Ok, the saddle valve was a bad idea, it's in now and sealed well. The water pipes in to the boiler only have a bell shaped fitting with a release valve type stem on the top of it. Other than that there is no other valve of any kind on the pipes. On the return lines there are only 2 tap type valves that I can hook a hose to for emtying the water into a sump pit or pail. Is this bell shaped fitting the fast fill valve? If it is, I take it the boiler should be turned off and cool and the other 2 zones shut off before I purge, correct? Will each zone have it's own circulator or is there one circulator per system? If one per zone then will a bad one get the water even part way, which is what is happening.
    Thanks

  5. #5
    Retired Defense Industry Engineer jadnashua's Avatar
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    Zoning can be done with either valves or pumps (or a combination of both). If a zone valve, it's possible it's not opening all the way. Many have a manual override on them. If yours do (and you have zone valves), you should be able to manually open it. If things then get hot, you know you need to either replace the zone valve or first, figure out if it is getting commanded to opened when the thermostat calls for it. It's possible it could be the thermostat isn't working for that zone, or it could be a control problem.

    You could have one or many pumps...only you can tell.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  6. #6

    Default

    There are valves on each zone and I believe a pump at the side of the boiler on the return pipe before it enters the boiler. The pipe just after the valve (going to the rads) gets hots whether I overide it or not and the thermostats are all good as I moved then around and they all worked. So, is that bell shaped fitting the fast fill valve? I still need to figure that out before I can flush the line. Can anyone answer my questions in post #4?

  7. #7
    Retired Defense Industry Engineer jadnashua's Avatar
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    It's much easier if you post a picture...scroll down when making a post to manage attachments.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

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