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Hoping that someone might be able to help me.
I have a sealed heating system comprising 15 radiators and hot water cylinder. In the last 18 months all radiators were replaced and plumbed using 10mm microbore pipe back to manifolds on 22mm flow and return pipes. The system is S plan with two heating zones and hot water.
The problem I am having is that the auto bypass lets hot water through in any combination. When both upstairs and downstairs heating is on the boiler stays on and good heat is achieved, although bypassing. When upstairs is on in isolation the bypass is open and the boiler starts short cycling and also does the same with hot water only.
Initially I was concerned that the microbore pipe was causing too much resistance of flow which was resulting in the auto bypass opening. However, the bypass also opens for hot water only which is not in small bore pipe so makes me think it is not this.
I have had the auto bypass replaced, so it is not a faulty valve.
The pump was re-used from the old system and is a 15/50, I wonder if this is not man enough to overcome the resistance of the new small diameter pipes? But this would not explain the bypass being open for hot water only?
My other line of thinking is that the heat exchanger may be clogged up causing a restriction, we are in a hard water area and had a period where the boiler was kettling last year.
Overall the heating and hot water work, but not as well or efficiently as I believe they could. Really I'd like to find a heating engineer in Norfolk who really knows their stuff, a couple of people local to me have been round and I've been advised to change the boiler which I just don't believe.
I have a sealed heating system comprising 15 radiators and hot water cylinder. In the last 18 months all radiators were replaced and plumbed using 10mm microbore pipe back to manifolds on 22mm flow and return pipes. The system is S plan with two heating zones and hot water.
The problem I am having is that the auto bypass lets hot water through in any combination. When both upstairs and downstairs heating is on the boiler stays on and good heat is achieved, although bypassing. When upstairs is on in isolation the bypass is open and the boiler starts short cycling and also does the same with hot water only.
Initially I was concerned that the microbore pipe was causing too much resistance of flow which was resulting in the auto bypass opening. However, the bypass also opens for hot water only which is not in small bore pipe so makes me think it is not this.
I have had the auto bypass replaced, so it is not a faulty valve.
The pump was re-used from the old system and is a 15/50, I wonder if this is not man enough to overcome the resistance of the new small diameter pipes? But this would not explain the bypass being open for hot water only?
My other line of thinking is that the heat exchanger may be clogged up causing a restriction, we are in a hard water area and had a period where the boiler was kettling last year.
Overall the heating and hot water work, but not as well or efficiently as I believe they could. Really I'd like to find a heating engineer in Norfolk who really knows their stuff, a couple of people local to me have been round and I've been advised to change the boiler which I just don't believe.
