Hot water in tank

[craigl]

I have a vented central heating system. The pump is positioned upstairs in the airing cupboard. I can achieve good heat on speed 1, but i am getting air in my system and when i check the tank the water is hot.I am not sure if its getting warm water from the water outlet or air overflow, i think its the outlet. Any ideas what could be causing this?

 

[kevplumb]

try the glass of water under the vent get sombody to switch the pump on and see if it sucks the water up

 

[craigl]

What if it does?

 

[kevplumb]

then its drawing air down the vent

 

[craigl]

what would cause it to do this?

 

[kevplumb]

ahh thats why you test first

 

[craigl]

would this cause hot water to re-enter the tank?

 

[kevplumb]

yes but it might not be your problem

do the test and post back

 

[craigl]

It is not air it is gas. I have put a Fernox cleaner in the system would this generate gas as it disolves the limescale. Presumably the hot water is from the gas expanding and pushing the water out of the system.

 

[brumylad]

why do you think the problem is air in your system ? is it because you need to bleed the radiators frequently ? or are there other symptoms

how long have you had this problem and/or what changes were made to the system to cause the problem (e.g. new pump)