Airlock Help

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Airlock Help

Post  feebet on Fri May 03, 2013 2:29 pm

Hi, I had another thread where boiler was heating store to correct(ish) temp. When central heating switched on, heat loss was greater than boiler could maintain.

Anyway, put cleaner in system 1 month ago and plucked up courage today to drain system down. From another thread on here I suspected the flexible braided hoses connecting the pipework to the boilermate. Sure enough I has to replace the braided hoses on the boiler flow and return and heating flow and return. The bore of the hoses was as little as 6mm dia down to 0mm !!

Replaced hoses with copper and refilled system. Took a while to fill CH system but when switched on the boiler heats the store up to >75 deg now. Switched CH on and store temp drops to 64 deg and then steadily climbs back up to the store temp cut off. Happy days !!

However I have NO hot water, the pump runs but there is no water flow through the pump and the heat exchanger so I am guessing airlock (HW was fine before draining down).

Anybody any ideas how to bleed HW circuit and can offer a description of which connections are which. I just have mains pressure cold water at the moment.

Thanks in advance.


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Re: Airlock Help

Post  mike on Fri May 03, 2013 2:51 pm

Well bleed the pump.
And you can try the top nut / connection right at the top.
But the washer can fail then it will leak. So be careful.
Or turn off pump valve and remove DHW pump.
When removed turn pump valves on to check for blockage etc.
Be careful.
Also under the DHW pump there is a brass housing.
This has a single check valve inside.
I have had one which was sticking.
And when removed it would stick when worked by hand every 5th time.
You could try a hose onto the DHW pump drain off.
But cover pump as water will mess it up from doc etc.
Try and keep trying.
Time consuming aren't they!
Mike

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Re: Airlock Help

Post  feebet on Fri May 03, 2013 3:24 pm

Thanks Mike

12 hours on this is enough for any man, so I've knocked it on the head for tonight !!

From your pointers;

Well bleed the pump.
And you can try the top nut / connection right at the top. - TOP OF THE PUMP OR THE TOP FRONT TANK CONNECTION THAT FEEDS THROUGH THE SWITCH IMMERSION CYLINDER ?
But the washer can fail then it will leak. So be careful.
Or turn off pump valve and remove DHW pump.
When removed turn pump valves on to check for blockage etc.
Be careful.
Also under the DHW pump there is a brass housing.
This has a single check valve inside.
I have had one which was sticking.
And when removed it would stick when worked by hand every 5th time.
You could try a hose onto the DHW pump drain off. - TRIED THIS NO JOY
But cover pump as water will mess it up from doc etc.
Try and keep trying.
Time consuming aren't they!
Mike

Thanks again
Paul

PS it still sounds like the header tank is trickling in so I guess my Boilermate is not 100% full yet ??

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Re: Airlock Help

Post  mike on Fri May 03, 2013 3:56 pm

Both what ever works
It will fill by the sound of it.
Mike

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Re: Airlock Help

Post  feebet on Sat May 04, 2013 9:54 am

Mike,

Looks like I just needed to be patient. BM2000 continued to fill overnight.

Hot water working today, you could hear the air inside the Switch immersion cylinder and then once circulated you could hear it bubbling back into the Boilermate. Couple of bursts with the hot tap making the HW pump run and we're back in business.

Checked readings on circuit board and WOW, what a difference. Not seen readings like these for a while;

Store temp now 75 deg C
Hot water temp indicated up to 67 deg C. Can't hold hand under hot water flow like you could before.

If you have a basic understanding of the system then don't be afraid to have a go. I for sure know a lot more about the BM2000 now then when I first started looking at my problems.

Thanks again Mike, what a help this site has been. Can I send you a virtual beer ?

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Re: Airlock Help

Post  mike on Sat May 04, 2013 2:18 pm

A whiskey would be better!
This is not my site.
It is a different Mike.
Well done

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