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Hi,
Can anyone tell me whether it's possible to get a 3 port zone valve with spring return that will connect to 35mm copper? (or maybe even the next size up). My googling has thusfar failed me. I did speak to one supplier until it turned out that theirs wasn't spring return; the supplier said that some of their competitors made such an item but he wasn't allowed to name them.
It seems that the bigger sizes are listed in inches, so for 35mm copper I need a 1.25 inch one (or 1.5 inch for the next size beyond that).
What it's for ...
We have an Aga that heats the hot water via 28mm copper using gravity feed. It has no thermostatic control. Before we can have a new boiler, I need to fix this as the supplier is saying they won't fit the boiler otherwise because it won't be Part L compliant.
The Aga is already sharing the heat between the hot water cylinder and a large radiator in the bathroom, so my plan is to fit a zone valve that when off, diverts all water to the radiator and allows none in to the water cylinder coil. When the tank thermostat demands heat, it powers the valve which sends water to the heating coil. That's the plan, anyway.
A 28mm zone valve would be an obvious and easy fit, but because the internal ports are narrower than the bore of the pipe I'm concerned that this could restrict flow too much, given that there's very little pressure with gravity feed. If the flow is reduced too much, I'm worried that the water might overheat in the Aga's heating coils and then boil in the pipe.
My thought was therefore to go up a size or two on the zone valve and then use converters to convert back to 28mm pipe. However, finding a zone valve big enough seems to be quite a challenge.
The reason for wanting spring return is that the thing is supposed to fail safe. In a power cut the Aga will continue to run, so it's essential that the spring can close off the feed to the hot water tank if this happens.
Failing that, I could get maybe a couple of 28mm ones and wire+plumb them in parallel, but that seems like an untidy solution.
Any suggestions?
Cheers,
Kingsley.
Can anyone tell me whether it's possible to get a 3 port zone valve with spring return that will connect to 35mm copper? (or maybe even the next size up). My googling has thusfar failed me. I did speak to one supplier until it turned out that theirs wasn't spring return; the supplier said that some of their competitors made such an item but he wasn't allowed to name them.
It seems that the bigger sizes are listed in inches, so for 35mm copper I need a 1.25 inch one (or 1.5 inch for the next size beyond that).
What it's for ...
We have an Aga that heats the hot water via 28mm copper using gravity feed. It has no thermostatic control. Before we can have a new boiler, I need to fix this as the supplier is saying they won't fit the boiler otherwise because it won't be Part L compliant.
The Aga is already sharing the heat between the hot water cylinder and a large radiator in the bathroom, so my plan is to fit a zone valve that when off, diverts all water to the radiator and allows none in to the water cylinder coil. When the tank thermostat demands heat, it powers the valve which sends water to the heating coil. That's the plan, anyway.
A 28mm zone valve would be an obvious and easy fit, but because the internal ports are narrower than the bore of the pipe I'm concerned that this could restrict flow too much, given that there's very little pressure with gravity feed. If the flow is reduced too much, I'm worried that the water might overheat in the Aga's heating coils and then boil in the pipe.
My thought was therefore to go up a size or two on the zone valve and then use converters to convert back to 28mm pipe. However, finding a zone valve big enough seems to be quite a challenge.
The reason for wanting spring return is that the thing is supposed to fail safe. In a power cut the Aga will continue to run, so it's essential that the spring can close off the feed to the hot water tank if this happens.
Failing that, I could get maybe a couple of 28mm ones and wire+plumb them in parallel, but that seems like an untidy solution.
Any suggestions?
Cheers,
Kingsley.
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