Temporary buzzing from contactor for storage heater - replace it?

tripswitch

Hi folks, The contactor (for the storage heating) in the breaker board in my apartment started buzzing at 1.30 in the morning two days ago.
I expected it to cut off at 9am when Nightsaver finishes but it didn't. So I tripped the switch on the panel for the storage heating and reset it. That stopped the buzzing. The heating worked as usual last night (ie. hot storage heaters this morning), with no buzzing from the contactor.
My question is whether that's something normal that happens to contactors and it's fine to leave it now, or whether I need to have it replaced immediately? (I'm assuming the latter, but wanted to double-check with you guys.)
thanks
(BTW, storage heaters suck in the Irish climate - they seem to need a gradual steady change in the temperature over the seasons, and we get too many big swings from day to day. I assume they're put in by developers because they're dirt cheap?)

Bruthal

They are usually ok when buzzing, usually caused by the actual metal core halves that come together having some dirt or possibly rust on them so the electro-magnet metal core faces dont 100% cleanly close. No harm to the actual contactors function occurs.

meercat

how old is your apartment?
it is usual for a slight humming sound from your contactor
it is the coil energizing and pulling in the contacts

its possible that your contactor is on the way out so maybe you should organize a replacement so you are not stuck in the future

Bruthal

I`d say the OP is talking about contactor buzzing or chattering, caused by the metal pole faces not cleanly closing, and usually can be cleared by re opening and closing, but may re-appear if the pole faces are starting to rust or have dirt on them. This causes 100hz buzz or chatter caused by the zero crossing points of the AC. Contactors have a shading ring to prevent this which would happen even with clean pole faces without the rings, but it will still chatter if their pole faces are not clean.


It wont affect the electrical contacts at all, just the head from listening to it if it is continous.

meercat

robbie7730 wrote: »

I`d say the OP is talking about contactor buzzing or chattering, caused by the metal pole faces not cleanly closing, and usually can be cleared by re opening and closing, but may re-appear if the pole faces are starting to rust or have dirt on them. This causes 100hz buzz or chatter caused by the zero crossing points of the AC. Contactors have a shading ring to prevent this which would happen even with clean pole faces without the rings, but it will still chatter if their pole faces are not clean.


It wont affect the electrical contacts at all, just the head from listening to it if it is continous.

brilliant robbie(as always)
you have a way with words

Bruthal

Thanks meercat:).

Sounds like the contactor may possibly have only closed at 1:30am as well, so maybe the storage heating is coming on 2 hours late too.

tripswitch

robbie7730 wrote: »

I`d say the OP is talking about contactor buzzing or chattering
(...)
It wont affect the electrical contacts at all, just the head from listening to it if it is continous.

Too right, it was a head wrecker that night. It hasn't happened since.

robbie7730 wrote: »

Sounds like the contactor may possibly have only closed at 1:30am as well, so maybe the storage heating is coming on 2 hours late too.

Spot on. I've no idea why it changed. It used to make a "clunk" sound around 10.30pm/11.30pm (summer/winter) as it came on. We've been away for a couple of months and now it's coming on at 1.30am instead. What determines the time it comes on?

Also, on the controller next to it, should the small dial marked DAY be set to "Const"? The green light next to it is on all day. (And the red one next to the NIGHT dial is flashing during the day. That dial is set to the mark between -2 and +2.)

tripswitch

tripswitch wrote: »

Also, on the controller next to it, should the small dial marked DAY be set to "Const"? The green light next to it is on all day. (And the red one next to the NIGHT dial is flashing during the day. That dial is set to the mark between -2 and +2.)

OK, this is a super common query and I've answered my own question by searching. (Doh!) Set the DAY one to the middle position (between -2 and 2) instead of "const" as it's not needed for storage heaters running on nightsaver rates.

M cebee

I was thinking alright from your first post that the timing must be off

the timing running late prob favours the domestic customer

Bruthal

M cebee wrote: »

I was thinking alright from your first post that the timing must be off

the timing running late prob favours the domestic customer

Id say it would alright

Red Alert

The "Day" dial, unless it's at Const, will only operate where there's a second "low tariff" period. This won't happen in Ireland - it's used only in the UK for some Nightsaver-like tariffs with a second burst during the day.

M cebee

An afternoon boost used to be common enough on the sangamo clocks

Red Alert

M cebee wrote: »

An afternoon boost used to be common enough on the sangamo clocks

Funny you mention that - my granny used to have it, the heaters would kick on from around 2-4 I think. The clock went bad at some stage, and it was replaced because there definitely was no afternoon boost in more recent years. Did the ESB do away with it, or just stop offering it to new NSH customers? Her apartment would've been built in the mid 1980's I think.

M cebee

don't know if it was an official thing

but it was common round here anyhow on separate nsh metering

tripswitch

Red Alert wrote: »

The "Day" dial, unless it's at Const, will only operate where there's a second "low tariff" period. This won't happen in Ireland - it's used only in the UK for some Nightsaver-like tariffs with a second burst during the day.

Thanks for all your help folks.

Now this bit has got me worried. I moved the Day dial off Const (to the midpoint of -2 and +2). The next morning our storage heaters were barely warm. Put it back to Const and the following morning they were toasty again.

Am I right in assuming they're taking in most of the heat on the more expensive day rate instead of on the Nightrate when they should be?

I'm also guessing that has something to do with the ESB clock for the apartment block being inaccurate, as the original problem made me notice that the contactor was only closing at 1.30am.

M cebee

I dont think they can charge on day rate if devireg is wired correctly