On Wednesday, February 24, 2021 at 11:25:35 AM UTC-5, Scott Lurndal wrote:
micky writes:
In alt.home.repair, on Tue, 23 Feb 2021 14:26:28 -0500, Tekkie©
wrote:


On Sat, 20 Feb 2021 03:05:37 -0800 (PST), Alexandre Verri posted for all of us
to digest...


I bought a house in Ireland two years ago and I still have some doubts about how the heating system controls should work.

My house has one thermostat and also a programmable mechanical timer. This is what I refer here as the control system. The actual behaviour of the control system is:

Regardless of the programmed timer, if the room temperature is less than the temperature set on the thermostat, the boiler and pump start working to heat the house.

If the room's temperature is bigger than the temperature set on thermostat and the timer fires, the boiler and pump start working to heat the house.

It seems a strange behaviour, this is not what I would have designed. I would prefer the following:

If the room's temperature is less than the thermostat and the timer fires, the pump and boiler should start working.

It's conceivable that they put the parts together wrong Conceivable,
It's conceivable and quite likely that neither of you have any
knowledge of Irish heating systems;

Do you? If so, since this is a DIY forum, why not help the poster and educate
others here? In heating systems the logical use for a thermostat/timer
combination is to have two or more time periods with differing temp set
points. With a boiler system that also provides domestic hot water, you
could have a timer to only enable the boiler to heat water for that during
certain time periods, eg not at night. That's how I see timers being incorporated.
So, what's so special about Ireland? And explain this:

"If the room's temperature is bigger than the temperature set on thermostat and the timer fires, the boiler and pump start working to heat the house. "

Unique physics in Ireland?



and that your speculation can
actually be damaging.

Recommendation is that the OP contact a reliable Irish HVAC
company for an inspection - most of them will do it for free
or a nominal charge.