From cold, 1 bar, it rises to about 1.5 bar when hot 70 degrees C. Is this right? While draining system we measured the output, about 86 litres plus some when I disconnected some pipes. Using 8 litre expansion vessel.
For a 3bar relief valve (normal one) and an initial charge pressure of 0.5 bar in the vessel, 75 litres of water would need 6.3 litres of vessel and 100 litres 8.3.
So if you are much over 86 litres, then you may need a larger or additional vessel. This will become apparent if the pressure climbs much over 2 - 2.5 bar
No, the 86 litres was from the open vented before I converted. As we drained we measured (in buckets), but that would have included header tank etc which is no longer in system.
Normally the design temperatures for a conventional (i.e. non-condensing) boiler are 82 degrees flow and 70 return. Generally radiators are sized to work with this and to be able to maintain room temperatures at -1 or -3 degrees outside.
It is desirable to run the boiler flow at this kind of temperature anyway because if the return approaches 54 degrees you are getting to the point where there will be condensing of the flue gases inside the boiler. In one not designed to take it like this, that would be bad news as it would lead to rapid corrosion.
It's possible on an older boiler that the thermostat is on its way out of course.
I would measure the return temperature and see what it's like when everything is up to temperature. If it's below 60 then something does need to be done.
I don't know whether the regulations in Ireland follow the UK, Francis (I know they do in some aspects of electricity for example), but there is a spec. for the max allowable pressure drop between the meter and the input of any appliance when running of no more than 1mB.
I would suggest that you check the incoming pressure at the boiler as well (i.e. on the input side of the regulator) to make sure that this is not being violated if you decide to wind up the regulator setting.
"FrancisJK" wrote | I have found it quicker and cheaper to get stuff shipped from | the UK to here, and that includes delivery. | Might be going over for the boiler "it's hand luggage Mr Ryanair"
At their fares vs excess baggage charges, be cheaper to take a couple of rugby teams over for the day, dismantle the boiler into 30 pieces and bring it back one piece each.
Or put little wheels on it and come back on the ferry as a foot passenger, tell them it's a gas-powered chair for the disabled.
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