by ericmark »
Tue Aug 13, 2024 11:52 am
I would agree with the advice given, but would also add in my own house rare for all radiators to be working together, all my radiators have a TRV fitted, and most with electronic heads, the system I will admit does not work A1 with my oil fired boiler, as it does not modulate like gas boilers do.
However the flow with gas boilers is not that high most of the time, one should use a differential thermometer on feed and return pipes, I actually do have one, but not the sensors, they got lost, so the problem is like with many DIY people how to set the lock shield valves?
I will talk about my parents house as it was gas with a modulating boiler. And maybe the problems will reflect your own. Problem one is the installers left all the lock shield valves wide open, so starting at what was likely the easiest radiator for the flow to go through, I turned the lock shield valve off, waited for pipes to cool, then turned on 1/4 turn at a time, until one pipe got warm, then moved to next, as they will affect each other, so this was a rough setting to start with.
All radiators now working, but a major problem with hall thermostat on the wall, there was no TRV in the hall, so idea is turn the hall radiator down gets rest of house warmer, and of course the reverse, but a hall has an outside door, so open door and hall got cold, turn up lock shield and hall got hot and rest of house cold.
Cure was add a TRV to hall radiator, now open hall door and hall gets cold, then TRV opens, the hall starts to warm, but before it reaches the wall thermostat temperature the TRV closes, so takes ages to get the last few degrees, allowing rest of house to get warm, now I was cooking with charcoal however still not A1.
Main problem was morning sun on bay windows, living room could hit 32 degs C, the radiator was too slow to cool, so changed the TRV heads to electronic, this helps in a few ways, the main was it was set in degs C not silly *123456 and the second it showed both target and current, so on a day when sun not shining through bay windows, set it so target did not exceed current, had two electronic heads, other one moved room to room, once the lock shield set, could put the mechanical TRV head back now there is only one item to set. And slowly moved around the house.
Net result the boiler now modulated as it was designed to do, and the TRV heads got the radiators just hot enough, they never got stinking hot except if heating had been off for a time, so since not so hot when sun shone, soon cooled down, room still could hit 24 degs C with sun shining but not the 32 degs it did hit. And other rooms were spot on, set at 20 and stayed at 20 degs C.
This house 9 electronic TRV heads, and times set for when rooms are used, so dinning room warm by 6 pm but cooling again by 7 pm, until next day, best is linked TRV heads to the wall thermostat, problem in this house, is hall cools too slowly, I can set how fast it heats with lock shield valve, but no way to control cooling rate. So I intend to fit a second thermostat in parallel with first.
