Boiler “exercising”

[Tim+]

Since the price of gas has gone up but I still have cheap rate electricity for a few hours at night I’m no longer using my boiler to heat my hot water. Consequently by boiler isn’t getting used at all at present.

I’m sure there’s no “right” answer but just curious as to whether other folk “exercise” their boilers in these situations just to stop things like pump and valves seizing up.

Now that I have my Wi-Fi switches it’s easy for me to program the boiler to run for 1 minute a day or 5 minutes once a week say. Is there any reason why a longer “exercise” like 5 minutes might be better than a short one?

Tim

[Theo]

My ASHP has a setting where it'll run the pump for default 30 seconds if it hasn't run in the last 7 days. In the current setup the zone valves aren't controlled by it (I have a todo to fix that), so they won't be opened.

I suppose you want to exercise the valves, the CH pump, the boiler internals (pumps/valves/hex/etc). Depends on your setup whether a call for heat is first opening a valve, which fires the pump, which calls for heat, which fires the boiler. If you ran it for 1 minute that cycle might only fire the boiler for seconds after waiting for zone valves to open etc.

Also I suppose there's the 'cold engine' effect, where combustion isn't clean until things are up to temp. Not sure how much that applies to boilers. But short cycling might cause some stresses.

I'd be tempted to go for 5 minutes a week if you can: maybe 5 mins heating then 5 mins hot water, or something like that.

Theo

[Nick Odell]

I've been doing fifteen minutes, once per month, to allow everything to get up to operating temperature. Would I be better off running it for a shorter period, more frequently?

Nick

[Brian]

Have you checked the numbers to see if using ‘ cheap’ electricity is cheaper than using you boiler to heat a tank of hot water?

I’ve not done it recently but, certainly in the past, E7 was still far more expensive than gas even in the days before condensing boilers.

Running the boiler to heat the hot water at the most convenient time for you - remembering a well insulated tank will stay hot for hours- would kill two birds with one stone.

[Tim+]

Yes.

Currently I’m paying 7.33p /kWhr on a flexible tariff for gas but on

5p/kWhr for electricity for four hours during the night. Add in boiler inefficiency and electricity is a clear winner for me at the moment. Those hours provide more than enough hot water throughout the day for us.

Tim

[R D S]

A real first world problem, it bugs me in summer that the towel rad isn't on so after a few uses your towel gets a bit damp and fusty, so I give the heating a short blast every couple of days before or after I jump in the shower, mindful too of what you mention.

I'm not sure how often we launder towels, I chuck mine in the wash when it seems necessary but it's more frequent in winter.

[Tim+]

Usually it’s possible to add an electric element to a towel radiator. We have one timed to come on for 2 hours a day in the morning.

Tim

[R D S]

Yes, I gave this some thought, would you fit this as well as CH or instead of? If as well as where would you fit the element? At the bottom I presume so CH return coming out of the top?

[Tim+]

As well as. Both flow and return are in the bottom of my radiator and the element is fitted in the flow.

See

Tim

[R D S]

Now then, I didn't know that was a thing!