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Some one will probably correct me but I think you look for an 11°C drop between inlet and outlet?
- Thread starter malcolm
- Start date
Some one will probably correct me but I think you look for an 11°C drop between inlet and outlet?
malcolm
& Clementine the Cat
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- 9,734
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the drainplugs usualy leak when hose is put on them. there cheap and nasty with no stuffing gland causing water to come through threads
It leaked a lot even with the valve tightly closed. I had been hoping that was the source of air into the system. But it doesn't drip when the valve is closed, so what you say makes sense.
Wonder where the air is coming from. Judging by the quality of the installation it wouldn't be surprising if there is a pipe under the floor (interlocking chip board and a pain to remove) that is impossible to bleed. But they surely must have had it working after installation.
brightspark
Member
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- 41,263
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- yarm stockton on tees
theres oxygen in the water to start off with especialy on indirect systems with open header tank in attic. sealed systems fare better .for less venting adding fernox or any anti corosive solution helps stop airbubles forming .wickes sell it quite cheap, fernox is double the price u just pay for the name 
hunter27
Pete
- Messages
- 902
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- Lancashire UK
As said with the poxy drain valves if it is accessible take the barrel out clean out any old washer stuck to the seat and just replace the washer do not over tighten just like a kitchen tap really. It is all to common for the old washer to disintegrate when undone or stick shut 
.
Just a point do not balance the system down to much,good flow keeps the system quieter, is easier on the pump and allows air to escape into the radiators, run the pump as slow as possible try on 1 once the air is out then up to 2 if 1 is not enough.
With the pump on the return the system is on a negative pressure and if the pump is powerful air can be pulled in (do not bleed rads with pump turned on)
Modern vented systems almost always have the pump on the flow pushing water around.
Pete
.Just a point do not balance the system down to much,good flow keeps the system quieter, is easier on the pump and allows air to escape into the radiators, run the pump as slow as possible try on 1 once the air is out then up to 2 if 1 is not enough.
With the pump on the return the system is on a negative pressure and if the pump is powerful air can be pulled in (do not bleed rads with pump turned on)
Modern vented systems almost always have the pump on the flow pushing water around.
Pete
