Hi folks, I’m in need of some sound advice.
We have recently had a ground floor extension and have had underfloor heating (company: JK UFH) installed throughout most of the downstairs. We have a few rads still left downstairs and the entire upstairs is still heated through rads.
We have a vented (gravity fed) central heating system (about 0.3 bar), heated from an oil fired Thermecon boiler. The header tank is in the loft and the boiler in the garage. It’s an S plan setup with two 2 port valves that control the flow to the CH and to the water heater tank (immersion).
The plumbers have just connected the UFH as a direct T -off from the flow (just after the boiler) and the return just before the boiler, as the UFH manifold is in the garage also.
The UFH has not been placed on a separate thermostat or controlled with a separate port valve, therefore it’s a dumb system and will only receive hot water if either the hot water tank or the CH are calling for heat. My plan is to get it on its own zone, however as things stand, I simply can’t get it to get hot at all. The best I’ve managed is 30 degrees while the boiler is running.
The pipework from the boiler to the manifold and CH is 22mm and all rads are on 15mm
My understanding is that I have the following options, however I’m a little in the dark as to the best course of action, so any advice and opinions would be welcome.
My Setup
We have recently had a ground floor extension and have had underfloor heating (company: JK UFH) installed throughout most of the downstairs. We have a few rads still left downstairs and the entire upstairs is still heated through rads.
We have a vented (gravity fed) central heating system (about 0.3 bar), heated from an oil fired Thermecon boiler. The header tank is in the loft and the boiler in the garage. It’s an S plan setup with two 2 port valves that control the flow to the CH and to the water heater tank (immersion).
The plumbers have just connected the UFH as a direct T -off from the flow (just after the boiler) and the return just before the boiler, as the UFH manifold is in the garage also.
The UFH has not been placed on a separate thermostat or controlled with a separate port valve, therefore it’s a dumb system and will only receive hot water if either the hot water tank or the CH are calling for heat. My plan is to get it on its own zone, however as things stand, I simply can’t get it to get hot at all. The best I’ve managed is 30 degrees while the boiler is running.
The pipework from the boiler to the manifold and CH is 22mm and all rads are on 15mm
My understanding is that I have the following options, however I’m a little in the dark as to the best course of action, so any advice and opinions would be welcome.
- I’m told that an additional pump is needed to get the hot water sent to the UFH manifold, however where would this pump go? before or after the T-off to the UFH manifold? Also, would a second pump run the risk of over pumping into the header tank, adding crap into the system? Or should this pump replace the current one on the first floor.
- Install more valves to enable the UFH to be diverted all hot water at the times it requires it, therefore going from a 2 valve to a 3 valve system. I’m thinking this will mean that the UFH will only get hot if the others are not calling for heat.
- Make the CH system unvented (pressurised) with an expansion vessel and filling loop. My worry here is that pressurising the system might find weakness in the pipework (house was built in 1990). Also I’m guessing that even after this is done, I still need to zone the UFH onto its own circuit.
- I’ve read that Installing a plate heat exchanger to the UFH would add pressure and get the heat through the system, however I’ve no Idea if this is a valid option and I’m assuming I still need to zone the UFH off.
- Some combination of the above
My Setup
