Poor fan convector performance...

[David]

Hi there,

Previously in the kitchen we had a 1kw electric plinth heater in the extension part of the kitchen which is nicely insulated etc. However it was replaced for a one which runs run of the heating; a Myson Kickspace 500, however despite it having a higher output it does very little to increase the temperature, even when it is running at full tilt with flow temperatures at 85=BAc.

I have been sorting out other issues on the system and most have all been sorted, it's just this which is not performing. I noticed that it is not piped like the the other radiators (trunk and branch) but instead like this:

this be the cause of the issue?

The system is all balanced correctly and everything else including the double radiator which the plinth heater takes its feed off heats up okay, except the front panel on the double radiator appears to feel very slightly cooler to the other.

[NT]

The picture doesnt really give any useful info. However something did cross my mind: the plinth heater's circulation is powered by the CH system pump, which stays off most of the time. The time constant of the plinth heater is short compared to that of the rads & rooms, so when the CH pump stops, the plinth heater's air output quickly declines from hot to warm to cool to cold.

I dont have enough experience with these heaters to know what the standard solution is. Running the CH pump when the plinth heater is going would greatly help. A relay would make that happen.

NT

[Newshound]

I replaced a rad with a kickspace heater, but ended up changing it back partly because of the excessive noise, partly the disappointing output. I never did much diagnostic work though.

[David]

System is all balanced and checked properly, 11=BAc differential. Pump speed is on the highest setting (Grundfos 15/60 built in to boiler)

[robgraham]

+1. It never gets switched on unless someone working in the kitchen kicks the switch. Personally a waste of money and fitting effort.

Rob

[David]

So it's not only me though, having said that though, a relative of mine has 2 Myson Kickspace 550's in their kitchen which is the main heat source and they work perfectly, the kitchen generally gets warm anyway by cooking etc but it'll be good to get the chill off in the mornings and the evenings.

[The Other Mike]

If it's simply wired to the mains, with a default loop across a couple of the internal terminals then it won't start the fan running until the water feed is above a certain temp and a thermal switch closes - this can be overridden by one of the front mounted switches. This can mean that it might not even switch on the convector fan until the boiler is nearly ready to cycle off. It then keeps the fan running until the thermal switch on the feed pipe drops below its threshold, so you get

boiler cycles on radiators warm up thermal switch closes convector fan provides a quick burst of hot air boiler cycles off (circulating pump may continue) convector fan keeps running giving rapidly cooling air thermal switch then opens fan stops repeat from start

Also, if it has no connection to a dedicated thermostat in the room and then back to the boiler to 'call for heat' then the heater will almost certainly not provide the specified performance.

If you have a wireless thermostat, move it temporarily into the kitchen and see if it makes a difference.