Rooms all at different temperatures#
Sometimes venues will discover that different rooms all are at different temperatures even though the thermostats and thermostatic radiator valves (TRVs) are all set the same.
We don’t supply enough thermal monitors for most groups to look at this, but if we did the air temperature might look something like this. In this particular case, we don’t know if all the thermostats and TRVs were calling for the same temperature, though.
There are several possible reasons for this.
Inaccurate TRVs. They break easily and the thermostats on them aren’t great, largely because they’re mounted on the radiator themselves. It is possible to move the thermostat off the radiator if required.
Wrongly sized radiators. It’s possible to calculate what size of radiator to use in a room depending on the size, the windows, whether it is north-facing, and so on. At least for houses, there are calculators online that will give you an approximation, although they don’t usually include how well draughtproofed the space is and the wind chill on an exposed wall that takes the weather. This can have a big effect in some community buildings. Often radiators are really sized by eye or by what will fit so some rooms will tend to be too cold or too hot.
System balance off. Ideally, the radiators that are calling for heat will all have the same temperature drop between the pipe going in (the flow) and the pipe coming out (the return). A balanced system will distribute the heating evenly, and if the radiators are sized well, that will keep everything nicely at the same air temperature. If the radiators are all sized well for the rooms, a balanced system will distribute the heating evenly. In an unbalanced system, the rooms with the smallest temperature drop can warm up too slowly or struggle to warm up at all. Unbalanced systems are less efficient and tempt users to turn up thermostats, wasting energy as a result. It’s hard to know what to do about this, though. In a space where every room is always meant to be the same temperature, the radiators can be balanced manually by adjusting the lockshield valves - and that might be appropriate, for instance, in a church that’s mostly just one big space and doesn’t have TRVs. In community buildings, we usually want to be able to vary the desired temperature in different rooms and selectively heat spaces in most community buildings. With each adjustment, the valve positions that would make the system balanced changes. It is possible to put in equipment that will balance a system automatically in this circumstance, but we have no experience with this and have never looked at pricing it up.
We look forward to our volunteer engineers helping us improve our thinking here, as increasingly, clusters of HeatHack venues are passing larger sets of thermal monitors around their spaces.
Be careful
If you decide manual balancing is called for, don’t do it yourself, especially if you have older radiators or lockshield valves that aren’t in a good state. You want a company to do it as they will be in a position to fix the valve if it starts leaking.
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