Hot water pouring into Feed & Expansion tank.
- Thread starter renard80
- Start date
Sponsored Links
No real reason to convert to a sealed system other than it is then guaranteed not to draw air (as the system is sealed).
Provided the system is piped correctly with the expansion and feed in the correct positions and the pump speed set to match the system, once the bypass valve is fitted all will be well.
Check the boiler installation manual and there will be a drawing of how it should ideally be done (around page 9). It says a minimum static head of 250mm (and this really is pushing the minimum) but the more the better as far as low head is concerned.
What it doesn't mention is the expansion pipe should rise around 450mm above the water level of the FE tank before dropping into it. An inverted feed (feed goes down and back up to join) is also advisable with a low static head.
Provided the system is piped correctly with the expansion and feed in the correct positions and the pump speed set to match the system, once the bypass valve is fitted all will be well.
Check the boiler installation manual and there will be a drawing of how it should ideally be done (around page 9). It says a minimum static head of 250mm (and this really is pushing the minimum) but the more the better as far as low head is concerned.
What it doesn't mention is the expansion pipe should rise around 450mm above the water level of the FE tank before dropping into it. An inverted feed (feed goes down and back up to join) is also advisable with a low static head.
A correctly plumbed installation which is clean will not pump over.
Pump speed setting is not critical; setting is more to do with adequate dispersal of water rather than 'setting reduction' to 'fix' pump over.
Pump over takes place if the vent is at higher pressure WRT feed/ expansion pipe. In many cases an old system that was gravity HW setup, then converted to fully pumped without plumbing alteration, leads to pump over.
To convert open vented to sealed system will bring its own problems, therefore I would stick with system as is but resolvv the plumbing issue
Pump speed setting is not critical; setting is more to do with adequate dispersal of water rather than 'setting reduction' to 'fix' pump over.
Pump over takes place if the vent is at higher pressure WRT feed/ expansion pipe. In many cases an old system that was gravity HW setup, then converted to fully pumped without plumbing alteration, leads to pump over.
To convert open vented to sealed system will bring its own problems, therefore I would stick with system as is but resolvv the plumbing issue
- Joined
- 19 Feb 2009
- Messages
- 369
- Reaction score
- 28
- Country
Another thing to be aware of with converting from open vent to sealed system is that the higher pressure could cause weak joints to fail in the system, joints which are 'dodgy' but are just about water tight under low pressure.
I'm talking from experience.
I'm talking from experience.
Sponsored Links
D
dextrous
The expansion vessel doesn't have to go in the loft - it can go anywhere that's convenient. In fact, it will mean that there will be no functional central heating pipework in the loft at all (it will all be removed as they would be considered undesirable "deadlegs") - you will only have the large cold water tank up there to deal with.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Similar threads
