Air Lock , Blockage or faulty pump ?


Postby MB » Mon Mar 10, 2008 9:57 pm

I recently removed a radiator and replaced it with a towel rail in the downstairs cloakroom. I drained the whole system down to carry out the work then refilled it and bled the system. I have hot water but the return pipe coming from the indirect cylinder is cold therefore no heating! The flow pipe is really hot and the pump is starting to make a whining noise. All the rads are filled with water but the central heating is just not circulating past the coil. It was ok before i carried out the work so i suspected an air lock but ive tried everything i can think of to clear it. The system is old 10mm microbore and full of muck. Ive cracked the flow and return nuts on the cylinder (while the system was off ) and it looked filthy. Anyone got any suggestions please ? Thank you.
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Postby ALDA » Tue Mar 11, 2008 7:29 pm

MB,

First, check F&E tank and valve are ok and suppling water to system.

Then, drain down again.

Refil and vent at pump, cylinder and rads.

Run heating.

Flush/drain again.

Re-fill and vent as before.

This may help get rid of black sludge and air in system.

If still air in system,

Try closing down all rads, put heating on full and open one rad and bleed and close and move to next rad. and so on till all rads are bled.
This will force air through and out of system.

ALDA.
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Postby MB » Thu Mar 13, 2008 8:10 pm

[size=12]Thanks Alda , ive done the things you have mentioned , the float valve in the f&e is knackered so ill need to replace that. Alot of the time im getting heat in the tails but it doesnt seem to want to circulate. Ive put 1l of sludge remover in the f&e and dropped the water out of one rad so i can get it into the system. Ive now got heat in 6 of 11 rads , ive got the boiler stat at max and the thermostat set to 30. Ive got a couple of rads that are just stone cold , could the microbore be proper blocked up somewhere? Ive had all the rad valves shut bar one ,connected cold mains pressure hose onto rad and tried to blow it out via a drain off . Ive also cut into the cold feed from the f&e and tried to blow it through from the loft out via a drain off on the ground floor. Any further suggestions? Your help is appreciated. MB
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Postby ALDA » Thu Mar 13, 2008 11:05 pm

MB,

AS YOU SAY, THERE COULD BE BLOCKAGE IN MICROBORE.

HAVE YOU FLUSHED OUT AND REFILLED SYSTEM SINCE ADDING THE SLUDGE REMOVER?

YOU COULD TRY FITTING HOSE TO EXPANSION PIPE AT F&E TANK AND HAVE THE PRESSURE SLOWLY INCREASED TO FORCE ANY AIR BACK THROUGH SYSTEM TO EXIT AT COLD WATER INLET IN BASE OF F&E TANK.
MAKE SURE THERE IS SPARE CAPACITY IN TANK TO COPE WITH ADDITIONAL WATER ADDED TO SYSTEM AND THAT OVERFLOW IS CLEAR JUST IN CASE YOU OR HELPER ARE NOT QUICK ENOUGH IN TURNING THE COLD WATER OFF.

THEN, RUN HEATING.

THEN YOU COULD TRY TO FORCE AIR OR BLOCKAGE OUT BY TURNING OFF RADS THAT DO HEAT UP.
DO OTHER RADS HEAT UP?
IF SO, THEN DO ALL RADS HEAT UP?

YES = OK, BALANCE SYSTEM.

NO = CHECK PUMP AND ANY VALVES IN SYSTEM ARE OPERATING CONSISTANTLY AND NOT FAILING INTERMITTENTLY.

A.
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Postby MB » Fri Mar 14, 2008 7:22 pm

Hi Alda , i fitted a new grundfos 15/60 pump today i have set this to three and turned the heating right up. i still had a couple of cold radiators so i closed the valves on the ones that were cold and drained the water out of them , then i opened the flow valve and the hot water came through into the rad. I let it fill and bled it then opened the other valve. Im not sure if its the sludge remover or not but today is the first day they've all come on. Theyre all working at the moment , i read on the sludge bottle that you should drain the system again after a while but im rather concerned that if i do this i will get all the problems again. Will it do the system any harm if i leave it in there? Once again your advice is greatly appreciated. MB
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Postby ALDA » Sat Mar 15, 2008 1:15 pm

MB,

THE SLUDGE REMOVER ENABLES THE PARTICLES OF SLUDGE TO BE LOOSENED AND HELD IN SUSPENSION IN WATER, READY TO BE FLUSHED OUT.

AS DE-SLUDGER CHEMICALS DEGRADE WITH TIME, SOONER OR LATER THE THE SLUDGE WILL START TO FALL OUT OF SUSPENSION AND TO CLOGG UP THE SYSTEM AGAIN.

SO IDEALY, DRAIN AND FLUSH THE SYSTEM AS WILL BE RECOMMENDED IN THE SLUDGE REMOVER MANUFACTURERS INSTRUCTIONS.

THE KNOWLEDGE AND METHODS YOU HAVE GAINED WITH YOUR RECENT EXPERIENCES SHOULD GIVE YOU THE CONFIDENCE TO DRAIN/FLUSH AND REFILL THE SYSTEM ONCE AGAIN.

I'AM SURE YOU WILL COPE.

BELIEVE AND ACHIEVE!!!

REGARDS,

ALDA.
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Postby MB » Mon Mar 17, 2008 1:33 pm

Thanks for the vote of confidence Alda. I've now drained down and refilled with no problems. God bless sludge remover and many thanks to you for your time and assistance. MB
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