Switch heating system off for summer

[Friday round]

Weathers warmed up and I’ve done some maintenance on the heating system to prepare it to be off till autumn. It’s a heat only, indirectly unvented, mostly with Wiser TRVs. I’ve put this checklist together but please advise if there’s anything else added. Also, I like most people wanting to save energy, adjusted the cylinder thermostat this winter down and ran the boiler flow at 55C. Thinking of upping it to 62C till winter again. Thoughts?

1. Clean magnetic filter
2. pour in remaining quarter bottle of inhibitor
3. bleed rads
4. top up water pressure if required
5. recharge air gap in megaflo
6. check the prv strainer
7. open all radiator TRVs and run both heating and hot water at the same time to diffuse inhibitor into system
8. set wiser programming to away mode.
9. fully open all manual TRVs (so valve pins dot get stuck like last year)

Last as mentioned above, I’m wondering if I should adjust boiler flow temp up, since it’s just for the hot water heating and I don’t think there’s energy savings to just boil water at a low temp.

 

[oldbutnotdead]

If you have any of the WiFi TRVs you might want to program them to move once a week
Hot water- again you could do with getting cylinder up to 65 + degrees once a week and running hot through all taps, showers etc (legionella prevention). Of course to do that boiler flow will have to be 65 or greater.....

 

[Harry Bloomfield]

There is no point/saving to be had, it turning the boiler temperature down below the cylinder temperature - if you have a stored HW system. The boiler needs to be around 10 C higher than the cylinder stat. setting, otherwise the boiler will just cycle, and never shut down. To avoid Legionella, cylinder temperature need to generally increased to more than 55C, at least once per week.

To supply the CH, yes you can save some, by turning the boiler temperature down.

 

[gas112]

so boiler doesnt do your hot water then or do you have solar to heat cylinder ?

 

[Rodders53]

Legionella is very unlikely in a domestic unvented HW system in the UK.
In any case stored temps above 50-55 C still kill them, it just isn't virtually instant like at 60+ C.
If you've had the cylinder stat down over the winter period and no Legionella why would the summer at same setting be different?

https://www.heatgeek.com/hot-water-temperature-scalding-and-legionella/ makes interesting reading and may put things into perspective for some other readers. NB Commercial premises including Hospitals and Care Homes have very explicit requirements from the HSE regarding HW storage and testing etc.,. that do not apply domestically.

From what I read wet ASHP installs typically have a weekly or fortnightly 'legionella' cycle pre-programmed for the HW: so that, to me, suggests a similar regime would be equally 'ideal' for any other system. Perhaps an immersion set to do 60 from the lower heated temp weekly or a programmable over-ride stat on the cylinder?

We occasionally need the CH to heat the bathrooms (although the en-suite has an electric towel rail that normally suffices in the warmer times, so can't don't shut it all down. We have timed HW to reheat just before our major use and during it... mine is on for just an hour a day (2 adults) and we never run out. It was on twice a day in previous years.

 

[Friday round]

so boiler doesnt do your hot water then or do you have solar to heat cylinder ?

Don’t understand your point. As I mentioned, it’s a heat only boiler.

 

[Friday round]

There is no point/saving to be had, it turning the boiler temperature down below the cylinder temperature - if you have a stored HW system.

Duh .

 

[Harry Bloomfield]

Duh .

Rather than quoting a small part of what I wrote, and adding Duh. Why not quote the entirety, and add some English comments?

 

[Friday round]

Dude. Not looking to start something here but you’ve gone down a path mansplaining about flow temp and cylinder thermostat differential and boiler cycling when I didn’t post anything about havin a boiler problem. My post is to primarily get tips on maintenance and putting the heating circuit of my system into ‘suspension’ for the next 6 months, and secondly, understand whether there is continued efficiency to running the boiler at a lower flow for summer months. As you say,

To supply the CH, yes you can save some, by turning the boiler temperature down.

then if I’m not running CH, but just the HW, then it doesn’t seem to be much efficiency gains to continue to run it at low flow. Therefore upping the flow temp just gets the cylinder heated faster, right?

 

[Harry Bloomfield]

Dude. Not looking to start something here but you’ve gone down a path mansplaining about flow temp and cylinder thermostat differential and boiler cycling when I didn’t post anything about havin a boiler problem. My post is to primarily get tips on maintenance and putting the heating circuit of my system into ‘suspension’ for the next 6 months, and secondly, understand whether there is continued efficiency to running the boiler at a lower flow for summer months. As you say,

My name is not, and never will be 'Dude'. So I'll leave you to it.

Anyone sensible would of course simply realise that turning a room stat low, will effectively shut the heating down.

 

[Friday round]

@Rodders53 Thank you for the thoughtful post. I agree on your point about Legionnaires. Also like you I ran the bathroom rads to heat/dry towels in previous years, but our baths are get adequate ventilation so will not run them this summer. Actually in previous years, I’d swap the manual TRVs with the Wiser ones which allowed turning the single bathroom rad on a fun gimmick. Only issue was that our hallway radiator isn’t on TRV and I’m reluctant to turn it down.

Just thinking again that maybe it isn’t best to just keep the CH entirely off over the period, but to probably run it/ exercise the valves periodically so things don’t get stuck.

 

[fixitflav]

Weathers warmed up and I’ve done some maintenance on the heating system to prepare it to be off till autumn. It’s a heat only, indirectly unvented, mostly with Wiser TRVs. I’ve put this checklist together but please advise if there’s anything else added. Also, I like most people wanting to save energy, adjusted the cylinder thermostat this winter down and ran the boiler flow at 55C. Thinking of upping it to 62C till winter again. Thoughts?

1. Clean magnetic filter
2. pour in remaining quarter bottle of inhibitor
3. bleed rads
4. top up water pressure if required
5. recharge air gap in megaflo
6. check the prv strainer
7. open all radiator TRVs and run both heating and hot water at the same time to diffuse inhibitor into system
8. set wiser programming to away mode.
9. fully open all manual TRVs (so valve pins dot get stuck like last year)

Last as mentioned above, I’m wondering if I should adjust boiler flow temp up, since it’s just for the hot water heating and I don’t think there’s energy savings to just boil water at a low temp.

Most of that is worth doing as general maintenance, but I don't see what it has to do with shutting the heating down for the summer (but still using the boiler for HW). Your room temperature controls will stop the CH coming on, and to make sure, you could turn the setpoints well down.

 

[Friday round]

@fixitflav Cheers. I probably was over thinking the effects of stagnating water in the rads and pipes for the period and I should just run it once a while anyways. On the Wiser, setting away mode effectively shuts down CH and I hope the 12C set point doesn’t get breached. That would be a horrible summer.