Cylinder hot water slow warming up

[vectraguy]

I have just fitted a Honeywell 2 way valve to my vented system, but the original system installer had fitted the feed pipe and return pipe to the cylinder water heating coil very close to the 2 way valve which meant it was impossible undo the 22mm nuts to the valve, and all of this is under the bedroom floor boards which doesn't give much room anyway.

After numerous attempts to get the valve out I gave in and had to cut a small section of the coil feed pipe out and I was then able to remove the valve, and fit the new one great !.

I then fitted a pipe connector to complete the hot water circuit and proceeded to bleed air from the radiators in the correct order up stairs and downstairs with plenty of air comeing out.

The radiators are working fine and the hot water is ok but seems to be taking a lot longer to get the cylinder up to temperature compared with prior to doing the job.

Is it possible that I still have some air in the coil, and would the bleeding operation also evacuate the coil as well as the radiators.

Any help much appreciated.
Regards vectraguy.

 

[oldbuffer]

Its quite possible you still have air in the coil within the cylinder.

If there is a bleed valve to the pipework (close to the cylinder, possibly a manual valve) use this to bleed the air out.

If not, carefully slacken the feed pipe into the cylinder (top pipe of the two) and let air and water out - old towels required to mop up. Re-tighten connection and should be OK.

Do the bleeding with the boiler and pump off and the motorised valve(s) open.

If the connection is really tight I would advise to get someone in to tee a bleed valve into the inlet.

 

[vectraguy]

Its quite possible you still have air in the coil within the cylinder.

If there is a bleed valve to the pipework (close to the cylinder, possibly a manual valve) use this to bleed the air out.

If not, carefully slacken the feed pipe into the cylinder (top pipe of the two) and let air and water out - old towels required to mop up. Re-tighten connection and should be OK.

Do the bleeding with the boiler and pump off and the motorised valve(s) open.

If the connection is really tight I would advise to get someone in to tee a bleed valve into the inlet.

Thank you oldbuffer for your response, I will do as you suggest because there is easy access to a screw connection at the top input to the coil.

I wonder if the air could be in the bottom (output) pipe because that one is not too easy to slacken or would any air always rise to the opened top pipe.

Regards vectraguy.

 

[vectraguy]

I have carried out the action suggested by oldbuffer, and on slightly cracking open the coil top feed produced water but no air at all.

I'm now not sure that the problem is infact air in the coil, and whilst under the floorboards I was able to use a temprature gauge on the coil input and output pipes surfaces.

The input read 50° C and output 40° C which must mean water is flowing through ok as I presume the lower output is due to heat transfer loss before returning to the boiler for re heat.

Regards vectraguy

 

[45yearsagasman]

May I suggest you raise the boiler thermostat to give you a flow temp of 70deg. 50 is nowhere hot enough. Cylinder stat set to 55-60.

 

[vectraguy]

May I suggest you raise the boiler thermostat to give you a flow temp of 70deg. 50 is nowhere hot enough. Cylinder stat set to 55-60.

Thank you for your kind advice, and until I carried out the 2 way valve fitting job the water for baths and showers has been just right, and we have a cylinder gauge which for ages has read 50° C and the water is just right for the wife and me.

This is what raised my concern because it now struggles to make 50° and takes twice as long.

I will increase the boiler thermostat control, and see if it reduces the wait for the morning shower.

Regards vectraman

 

[vectraguy]

May I suggest you raise the boiler thermostat to give you a flow temp of 70deg. 50 is nowhere hot enough. Cylinder stat set to 55-60.

Thank you for your kind advice, and until I carried out the 2 way valve fitting job the water for baths and showers has been just right, and we have a cylinder gauge which for ages has read 50° C and the water is just right for the wife and me.

This is what raised my concern because it now struggles to make 50° and takes twice as long.

I will increase the boiler thermostat control, and see if it reduces the wait for the morning shower.

Regards vectraman

I increased the boiler thermostat from the previous "5" to the maximum "6" on our Worcester Greenstar 30 CDI and this morning looking at the cylinder gauge found it had reached the desired 50° C.

This is fine, but it obviously used more gas to achieve what has always happened during the past five years on setting "5".

I am now satified the sudden change in performance is nothing to do with air in the system, but rather sludge which during the recent pipe and two way valve surgery has moved causing a partial blockage especially in the cylinder coil.

I am going to charge the system with Sentinel X400 and let it circulate for a couple of weeks and then apply Sentinel X100 inhibitor,and hope this sorts it out.

Regards vectraguy.