Thermal store installation

[m550344]

I have recently installed a new 300l vented thermal store, swapping out the standard 160l vented cylinder. Existing 4 gallon F & E tank in the loft was also with a new 25 gallon tank. The install pretty much used all the existing piping but I am not sure about the re-use of the existing vent piping back into the F & E. I understand that heating the cylinder will cause expansion and hence the venting into the F & E, but should I expect hot water water to vent into the F & E tank after just 20 mins of heating the thermal store?

I have read through numerous threads about venting, expansion capacity theory etc but now need to get a practical answer as to whether I need to get my plumber back to check the vent side of things. The F & E is not overflowing, but just questioning the hot water into the F & E.....

 

[Bernie2]

No! The vent probably needs adjusting to be made higher over the feed cistern water level.
Water expands up the vent as well as back into the supply cistern. And as it expands by about 1/24th in volume its not got enough room to expand up the vent probably because you now have a bigger volume cylinder.

But also check there are no valves turned off or blockages in, the heat store cold feed. If a certain amount of expansion water can't go back into the feed cistern as it backs up the cold feed. Its only got the vent to get out of.

 

[Jimbob]

Definately sounds like a higher vent is needed

 

[stevetheplumber]

I have recently installed a new 300l vented thermal store, swapping out the standard 160l vented cylinder. Existing 4 gallon F & E tank in the loft was also with a new 25 gallon tank. The install pretty much used all the existing piping but I am not sure about the re-use of the existing vent piping back into the F & E. I understand that heating the cylinder will cause expansion and hence the venting into the F & E, but should I expect hot water water to vent into the F & E tank after just 20 mins of heating the thermal store?

I have read through numerous threads about venting, expansion capacity theory etc but now need to get a practical answer as to whether I need to get my plumber back to check the vent side of things. The F & E is not overflowing, but just questioning the hot water into the F & E.....

think its just the heat traveling up the cold feed rather than pumping over my ts system warms the fe tankslightly as its only a couple of feet above if the cylinder fitted correctly and insulated it isnt a problem .It may be the primary pumps set to high
mine is a bit heath robison as im running it from a system boiler so cant adjust the pump

 

[m550344]

I have to assume now its the vent height, is there a practical way of increasing the vent height as the existing venting is in a confined area?

 

[helpsy]

Vent pipe if I recall from my course, for the F+E tank should be 450mm above water level

 

[HTB]

or if possible reduce the speed on the pump or restrict its flow (assuming the pump is in the right position relative to to vent on the system ie downstream not upstream)