I put this post in the wrong forum!
Having self-built an annexe I am now modifying the central heating system. I would welcome advice on using a variable speed pump. The boiler is a sealed-system condensing oil-fired Hounsfield in an outbuilding.
The system was already complicated having separate upstairs and downstairs zones in the main house and again in a granny wing before I added the annexe which will also have upstairs and downstairs zones. So that is 6 zones with three programmers. Rads are fan-convectors or Finrad ckirting rads so system water content is low. There are no TRVs. The demand on the system is very variable as the main house is in regular use but the other parts are occasional so a variable speed pump that automatically adjusts with load would be good. The upstairs heating is seldom used.
The zones are controlled via the programmers using Myson valves which have auxiliary switches.
I have been careful to avoid closing off all the zones and have used the valve auxiliary switches in series with the pump. This worked well with the existing 25 year-old Grundfos Super Selectric 15/60 130, but with the new annexe I thought it might be prudent to add a new pump and a single bypass valve at the pump. I have in mind to replace the pump with a Grundfos Alpha 25-60 130 with Auto Adapt. I bought an automatics bypass valve but have since read that this is unsuitable. I have since bought a Taconova fixed /mechanical bypass
I have read conflicting statements about using this pump with a bypass.
Advice welcomed.
Having self-built an annexe I am now modifying the central heating system. I would welcome advice on using a variable speed pump. The boiler is a sealed-system condensing oil-fired Hounsfield in an outbuilding.
The system was already complicated having separate upstairs and downstairs zones in the main house and again in a granny wing before I added the annexe which will also have upstairs and downstairs zones. So that is 6 zones with three programmers. Rads are fan-convectors or Finrad ckirting rads so system water content is low. There are no TRVs. The demand on the system is very variable as the main house is in regular use but the other parts are occasional so a variable speed pump that automatically adjusts with load would be good. The upstairs heating is seldom used.
The zones are controlled via the programmers using Myson valves which have auxiliary switches.
I have been careful to avoid closing off all the zones and have used the valve auxiliary switches in series with the pump. This worked well with the existing 25 year-old Grundfos Super Selectric 15/60 130, but with the new annexe I thought it might be prudent to add a new pump and a single bypass valve at the pump. I have in mind to replace the pump with a Grundfos Alpha 25-60 130 with Auto Adapt. I bought an automatics bypass valve but have since read that this is unsuitable. I have since bought a Taconova fixed /mechanical bypass
I have read conflicting statements about using this pump with a bypass.
Advice welcomed.
