R
Richard at Home
Hi
I was hoping someone could pass me a little advise please
I have a STD open vented hot water system with a hot water tank and a large cold water tank in the loft
this is the problem i have and i am trying to find a way to resolve it
The cold water tank is at least 15 foot above the Hot water tank
28mm Cold water feed to the bottom the hot water tank
This is the problem
If i run off the hot water in the bath 22mm it appears that the water flow seems to exceed the pressure of the cold water feed pressure and air is sucked into the pipe work while running the hot water off.
This does not cause a major problem. does not stop water flow but its just a pain to be honest. you can see the air in the hot water as the bath fills.
Turning the flow of the hot water down reduces the problem significantly.
it is as though the flow rate of the hot water goes into siphon flow creating a negative pressure against the main vent inlet and just drags air into the system.
This then places an air lock in the hot water feed the next time the shower pump kicks in that i know is not good for the pump
I know this is not the solution but it is how i found the route cause
If i place a Temp seal over the Air Vent pipe wile running the bath the problem is resolved. Obviously this was removed after experiment.
I cannot raise the height of the vent pipe any more as it is high in the loft as it is.
We can not use a combo system as the mains water pressure is very poor into the property
I just wondered if there are any options or subjections anyone could make that i may have missed
Thanks Everyone.
Best Regards
Richard
I was hoping someone could pass me a little advise please
I have a STD open vented hot water system with a hot water tank and a large cold water tank in the loft
this is the problem i have and i am trying to find a way to resolve it
The cold water tank is at least 15 foot above the Hot water tank
28mm Cold water feed to the bottom the hot water tank
This is the problem
If i run off the hot water in the bath 22mm it appears that the water flow seems to exceed the pressure of the cold water feed pressure and air is sucked into the pipe work while running the hot water off.
This does not cause a major problem. does not stop water flow but its just a pain to be honest. you can see the air in the hot water as the bath fills.
Turning the flow of the hot water down reduces the problem significantly.
it is as though the flow rate of the hot water goes into siphon flow creating a negative pressure against the main vent inlet and just drags air into the system.
This then places an air lock in the hot water feed the next time the shower pump kicks in that i know is not good for the pump
I know this is not the solution but it is how i found the route cause
If i place a Temp seal over the Air Vent pipe wile running the bath the problem is resolved. Obviously this was removed after experiment.
I cannot raise the height of the vent pipe any more as it is high in the loft as it is.
We can not use a combo system as the mains water pressure is very poor into the property
I just wondered if there are any options or subjections anyone could make that i may have missed
Thanks Everyone.
Best Regards
Richard