I want to convert a gravity hot water system to fully pumped to include a new cylinder. Complicated by the fact the old cylinder is a primatic. Current system layout is cold water storage tank in attic, primatic cylinder on 1st floor and boiler on ground floor. This is what I plan do.
From the boiler use the current HW flow and return pipes for the supply pipes and cap off the old CH pipes. As they are 28mm reduce them to 22mm. Add appropriate valves to feed HW and heating and room and cylinder thermostats.
The pump is currently on the CH return pipe so this will be moved to the flow pipe.
Put new f&e tank in attic. However, although it’s a primatic cylinder there are already two vent pipes which both currently discharge into the cold water storage tank. One vent pipe is teed off the HW outlet from the cylinder. The other is teed off what I assume is the HW flow pipe to the coil in the cylinder. Therefore, can I simply move this vent pipe over to the new f&e tank or does this pipe need to run all the way down to the boiler?
Other issue is where to connect the cold feed from the new f&e tank into the system? Could this be teed into the return pipe close to the cylinder coil or should it be run all the way down to the boiler? I understand that there is some issue about positive/negative pressure with regard to where the vent pipe, cold water feed pipe are connected in relation to the pump.
Not sure whether it's relevant but the CH is a single pipe system.
Thanks for any responses.
From the boiler use the current HW flow and return pipes for the supply pipes and cap off the old CH pipes. As they are 28mm reduce them to 22mm. Add appropriate valves to feed HW and heating and room and cylinder thermostats.
The pump is currently on the CH return pipe so this will be moved to the flow pipe.
Put new f&e tank in attic. However, although it’s a primatic cylinder there are already two vent pipes which both currently discharge into the cold water storage tank. One vent pipe is teed off the HW outlet from the cylinder. The other is teed off what I assume is the HW flow pipe to the coil in the cylinder. Therefore, can I simply move this vent pipe over to the new f&e tank or does this pipe need to run all the way down to the boiler?
Other issue is where to connect the cold feed from the new f&e tank into the system? Could this be teed into the return pipe close to the cylinder coil or should it be run all the way down to the boiler? I understand that there is some issue about positive/negative pressure with regard to where the vent pipe, cold water feed pipe are connected in relation to the pump.
Not sure whether it's relevant but the CH is a single pipe system.
Thanks for any responses.