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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 7541
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Installed a firebird oil combi boiler ran well week but then

Customer Question

Installed a firebird oil combi boiler ran well for a week but then stopped.tride to re start no haven't gone to lock out and the pumps ar running any idea
JA: I'll do all I can to help. Tell me a bit more about what's going on so we can help you best.
Customer: The boiler was running fine
JA: Is there anything else important you think the HVAC Technician should know?
Customer: Not realy
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Submitted: 4 months ago.
Category: HVAC
Expert:  Phil replied 4 months ago.

So far it sounds like a few stray air bubbles have collected at the same high point in the domestic hot water loop, and blocked the water flow, the boiler will not come on if the flow switch does not detect 0.6 gpm water flow.

Bleed all the air vents in the system, if that fails get back to me with more details and photo's of the piping... I can coach you on discovering what the problem is.

Hold your rating until we get this sorted out for you please.

Expert:  Phil replied 4 months ago.

Ooops I meant air in the central heating loop, not the domestic hot water loop.

Customer: replied 4 months ago.
The hot water doesent work aswell
Expert:  Phil replied 4 months ago.

Domestic hot water will not work if the pump is not moving water through the main gas fired heat exchanger which is in the central heating loop. we need to check for air locks first, (50% chance thats the problem)... we go from there if there are no air locks in system, air locks on a new system is the primary suspect.

Look your manual over for venting air from the system... we can go from there as needed.

Customer: replied 4 months ago.
Taken all the air from the system nothing.should the limit stat have a light when on every thing else seem ok
Expert:  Phil replied 4 months ago.

Thanks, ***** ***** limit stat light is on, then it is tripped...running with air in the system will cause that as well.

Tell me in great detail what type of radiators or under floor heating you have, and precisely what you did, in detail, to get the air out... and what the water pressure inside the boiler was in that time frame.

We can go from there.

Customer: replied 4 months ago.
The radiators ar the old cars iron no thermostatic valves drained the boiler side of the system re filled air was coming out of the automatic valve on the boiler and switch on but no joy pump were quit noise to start with but then settled down.the limit stat is ok
Expert:  Phil replied 4 months ago.

Thanks, that approach will leave you with a lot of air in the system. You do not drain and refill to get rid of air. you fill the system, so that it is under 1.5 bar pressure, then open the *tiny air bleed valves near the top of each radiator, until a tiny squirt of water comes out.... the entire time making real sure that you still have 1.5 bar or a bit more water pressure at the boiler.

Then.... and very importantly... run the pump for a while and *repeat this bleed process... until you get nothing but water from each of the air bleeds at the top of each radiator and at the pressure relief valve on the boiler, and from **any other** high point in the piping... each high point must have an air bleed.

High point is any place a bubble can form and get trapped ... and inverted U shape for instance.

Let me know how it goes.

Expert:  Phil replied 4 months ago.

Use the paper clip icon at the right end of the tool bar, to send me a few photo's of one of the radiators so that I can see each end of the radiator, top to bottom.

You might be trying to use steam radiators in a hot water application or some such.

Use the 'attach files' link to the left of your send button if there is no paper clip icon.

Customer: replied 4 months ago.
I don't think it anything to do with the radiators it work fine for a week they had two bath full of hot water and it went on the blink ar you saying i need to drain the whole system and then refill
Expert:  Phil replied 4 months ago.

Air **migrates** in the system, it can be sporadic air locks. The measures that you have described so far absolutely guarantee air in the system... the odds that air in the system is causing the problem are in the 98% range....and remember that is me saying this blind, without seeing your job... but I do have 55 years as an installation contractor and consulting manufacturers in the US and Japan

You should not drain the system, in fact, do not drain the system. Instead pressurize the system to 1.5 bar and follow the bleed procedure that I specified.

If you will send me pictures that will help immensely.

Customer: replied 4 months ago.
I checked the automatic valve on the boiler while filling up to 1.5, couldn't hear air coming out could this be fault that air cannot come out and the boiler doesent fire
Expert:  Phil replied 4 months ago.

Yes, that could be the problem, as I stated earlier you need to open the TINY air vents at the top of each radiator to let the air out.... air will not come out if the air vent is closed.

I also need photo's as detailed earlier...

Expert:  Phil replied 4 months ago.

There are several dozen different radiator types, some for steam, and some for hot water... I need those photo's to see what you have.

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