I'd be grateful for some professional advice - can't think my way any further on this.
We have old-style vented gravity DHW and pumped CH system with little in the way of controls. Boiler is only 6 years old and fine, and I prefer to stay vented. There are reasons why I have to upgrade the whole system, but first step is to go fully-pumped to improve cylinder reheat and get abreast of current regs.
The difficulty in replumbing/rewiring is access. The boiler and pump for CH are on ground floor alongside programmer. The cylinder is on the first floor. The pipe (and cable) run to the cylinder is inaccessible, sealed into a five metre wide flat roof.
If I move the pump into airing cupboard by cylinder and fit a Y valve, I can’t get a cable to it from the boiler. I looked at the Grundfos twin pump (‘Pump Plan’) which has a dedicated Danfoss wireless kit for control, but this still needs wired connections to the boiler.
I am thinking maybe I could fit the twin pumps on the primary and CH circuit at the boiler, but this couldn’t be on the flow which runs up to the vent and feed. Is it feasible to fit it on the returns, despite the negative pressure this would make? I know this is not good practice. Or will I just have to remove some plasterboard to get into the roof space?
Also - I’m surprised the system was ever built like this since it has 5 metres of near-horizontal pipe on the flow/ vent – is this a big problem? (It’s been there since the 1970s.)
We have old-style vented gravity DHW and pumped CH system with little in the way of controls. Boiler is only 6 years old and fine, and I prefer to stay vented. There are reasons why I have to upgrade the whole system, but first step is to go fully-pumped to improve cylinder reheat and get abreast of current regs.
The difficulty in replumbing/rewiring is access. The boiler and pump for CH are on ground floor alongside programmer. The cylinder is on the first floor. The pipe (and cable) run to the cylinder is inaccessible, sealed into a five metre wide flat roof.
If I move the pump into airing cupboard by cylinder and fit a Y valve, I can’t get a cable to it from the boiler. I looked at the Grundfos twin pump (‘Pump Plan’) which has a dedicated Danfoss wireless kit for control, but this still needs wired connections to the boiler.
I am thinking maybe I could fit the twin pumps on the primary and CH circuit at the boiler, but this couldn’t be on the flow which runs up to the vent and feed. Is it feasible to fit it on the returns, despite the negative pressure this would make? I know this is not good practice. Or will I just have to remove some plasterboard to get into the roof space?
Also - I’m surprised the system was ever built like this since it has 5 metres of near-horizontal pipe on the flow/ vent – is this a big problem? (It’s been there since the 1970s.)