Effects of lower system temperature on the boiler pump?

pieroabcd

Hi,
I kept the boiler heating temperature at 55 degrees and I verified that it works well in this  house, but I also noticed that the time that it took to raise the temperature by 2 degrees went from < 2 hours at 60° to 3 hours at 55°, that made the boiler hum for longer.

I'm wondering if this can lead to more wear and tear and higher chances of damage to the distribution pump.

I was also wondering what happens if the pump breaks after the 2035 deadline (assuming that we actually get to it): will I still be able to replace it keeping the gas boiler operational?

Any ideas?

Exodi

I believe the 2035 deadline you refer to is regarding the sale of new boilers, not the service or provision of spare parts.

Lowering the boiler temp isn't a cheat code to save money with no downside, as you have found out. I'd think lowering boiler temperatures is most effective where people are putting the radiators on for a set amount of time (e.g. 30 mins upstairs before bed) rather than people who are trying to achieve a set temperature in the shortest amount of time.

55 is about as low as you can go before people will start to worry about things like Legionella (though some dismiss this risk). If it's taking nearly double the time to heat up, I'd imagine 60 might end up being more efficient for you. 

ThisIsWeird

I'd imagine the extra running time of the pump will be largely offset by the reduced stress of the lower working temp. This certainly isn't going to be the cause of it failing sooner than it should.

Is this an external pump? If so, replacement is a DIY-doddle. In any case, just don't worry.

2035 is likely to have a whole new range of heating options, and your boiler will be a local attraction if it's still running :-)

You raise a good point, tho' - if you keep lowering the flow temp, there will come a point where your boiler and pump will be running pretty constantly, and still not meet demand - you don't want to get there. But, from what you say, you appear to have found a sweet spot. Keep an eye on it, tho', as the temp falls further - you may need to raise the flow temp to keep things level.

pieroabcd

Oh yes, i suspect that I'll need to raise again to 60° when winter comes.
The pump is internal to the boiler, a gracious all in one :-)

tacpot12

pieroabcd said:

Oh yes, i suspect that I'll need to raise again to 60° when winter comes.
...

This is exactly what "weather compensation" does automatically for you. You might look to see if your model of boiler cna be fitted with an outdoor weather sensor and set for weather compensation.

Albermarle

pieroabcd said:

Oh yes, i suspect that I'll need to raise again to 60° when winter comes.
The pump is internal to the boiler, a gracious all in one :-)

Winter seems to have already arrived ! I have increased our flow temperature yesterday from about 58 to about 63 degrees.
I have to say 'about' because on the more basic WB boilers there is only a dial with no temperatures marked on it, and nothing fancy like a digital readout. 

FreeBear

pieroabcd said: The pump is internal to the boiler, a gracious all in one :-)

Most boiler manufacturers use "off the shelf" parts like pumps and fans. My boiler, a Viessmann, uses a Grundfos UPM3 pump. The fan is made by Papst, and many of the sensors are bog standard components available from the likes of RS or Farnell.

Just the control board, combustion chamber, gaskets, and plastic parts would need to be sourced from Viessmann. However, finding a Gas Safe engineer prepared to use parts sourced from elsewhere would be a challenge. And yes, if the casing needs to be opened up to gain access, a GS engineer has to be used.

rob7475

Exodi said:

I believe the 2035 deadline you refer to is regarding the sale of new boilers, not the service or provision of spare parts.

Lowering the boiler temp isn't a cheat code to save money with no downside, as you have found out. I'd think lowering boiler temperatures is most effective where people are putting the radiators on for a set amount of time (e.g. 30 mins upstairs before bed) rather than people who are trying to achieve a set temperature in the shortest amount of time.

55 is about as low as you can go before people will start to worry about things like Legionella (though some dismiss this risk). If it's taking nearly double the time to heat up, I'd imagine 60 might end up being more efficient for you. 

Legionella isn't a risk in a heating system as there are no water outlets. Legionella only really poses a risk if contaminated water is released as a spray. Within a heating system the water doesn't get released so there's no risk.

Depending on what boiler you have, weather compensation is worth looking into as it will adjust the flow temperature automatically depending on the outside temperature. At the minute our boiler is ticking over at a 45 degree flow temperature. Once the temperature drops overnight though, it'll run at around 70 - 80 degrees for a short while in the morning to heat the house quickly.

Belenus

pieroabcd said:

Oh yes, i suspect that I'll need to raise again to 60° when winter comes.
The pump is internal to the boiler, a gracious all in one :-)

Do you have an installers or a manufacturers warranty for the boiler?

If yes, then that should cover you if the internal pump fails provided the manufacturer or installer is still around.

Like you I vary the boiler flow temperature. I keep it lower in summer and warmer weather and raise it during winter or colder weather.

pieroabcd

The boiler is now 10 years old. 
The GE will service it next month and will do the gas safety certificate, but to me it's unclear if the servicing is a warranty to have free replacements if something breaks. 

Albermarle

rob7475 said:

Exodi said:

I believe the 2035 deadline you refer to is regarding the sale of new boilers, not the service or provision of spare parts.

Lowering the boiler temp isn't a cheat code to save money with no downside, as you have found out. I'd think lowering boiler temperatures is most effective where people are putting the radiators on for a set amount of time (e.g. 30 mins upstairs before bed) rather than people who are trying to achieve a set temperature in the shortest amount of time.

55 is about as low as you can go before people will start to worry about things like Legionella (though some dismiss this risk). If it's taking nearly double the time to heat up, I'd imagine 60 might end up being more efficient for you. 

Legionella isn't a risk in a heating system as there are no water outlets. Legionella only really poses a risk if contaminated water is released as a spray. Within a heating system the water doesn't get released so there's no risk.

Depending on what boiler you have, weather compensation is worth looking into as it will adjust the flow temperature automatically depending on the outside temperature. At the minute our boiler is ticking over at a 45 degree flow temperature. Once the temperature drops overnight though, it'll run at around 70 - 80 degrees for a short while in the morning to heat the house quickly.

I think the poster was probably assuming that the boiler was also heating a hot water tank, as is often the case. Normally the heating and hot water are using the same boiler temperature, so at a flow temp of 55, the hot water might only be getting to 50 (ish).
Probably still safe enough in a domestic setting where the hot water is used everyday, but the official recommendations are that you go to 60/65 ( depending on what/where you read) .