Myson kickspace 600 blowing intetmittantly

[Pisces67]

Have a kickspace which blows intetmittantly. Goes on for about 20 s then off and comes on again later only for short period again. Checked flow and return and appears return is only luke warm. New flexis replaced with a bigger bore. Could it be the kickspace that's blocked?

Thanks

 

[oz-plumber]

It may have a temperature sensor on the flow pipe, which cuts out when the water temperature is below ( say ) 50C.
This is to stop the unit blowing cold air.

Either get the temperature of the water hotter for the unit to operate, or by-pass the temperature switch.
Some of these are 240 V connected inline with the fan - so be careful if by-passing switch.

 

[Last Plumber]

Could be:-
Faulty stat
Inadequate/restricted flow
Water temperature too low.

 

[Pisces67]

If the heater is coming on then the water temp is hot enough, but not staying on long enough. Is this due to the return which could be restricted and in turn back up heat then knock the thermal switch off. What does the thermal switch look like

 

[snowhead]

I'd say the heater core is partially blocked and needs cleaning out or replacing.

With the fan off there's enough flow through the heater to cause the stat / switch to switch the fan on.
As soon as the fan starts there's too much heat being blown off the coil and the fan will stop, coil temperature will rise, stat will switch, fan will come on etc etc.
The cycle will repeat for ever.

The waterways in those types of heaters are quite small and easilly block.

The simplest / cheapest way to fix it would be to remove the coil and take it to a car radiator repairer, they're used to working with the same type of coil.
They may be able to flush it out and or descale it, if not they'd be able to open the coil up and clean it out.

Check the price of buying a new coil then try a radiator repairer, see how it compares.

 

[Pisces67]

Sounds logical your diagnosis. Is there anything I can do myself to the unit once I've removed o it from the flexis, in terms of cleaning a/declogging the coil

 

[snowhead]

Maybe hosepipe onto flow and then onto return in and out of the coil to try and move the blockage / scale

 

[Last Plumber]

With these being at the low point of the system, they are prone to collect sediment as is being discussed.
Is the system water dirty?
It can be a case of balancing. Have there been any alterations?
Has this just happened or got worse over time?
Did it ever work well?

 

[Pisces67]

Lowest point on system, has worked previously but gradually proformance has deteriorated in terms of coming on sufficiently, water in system quite clean and no sludge,. Recently took off radiator for decotating and clean water with a little black sediment in it.

 

[Pisces67]

Took the heater out today, and possible cause is blocked return flexi, heater itself seems OK but washed it threw anyway. Return flexi unblocked using a bit of wire. Whisky isolator open.
Is there anyway of identifying which thd glow as nd return are on tje kickspace, myson have said its thd top
Hole but not hi g in the manual?
[automerge]1597949357[/automerge]
Should read with isolator valve open on flexi.

Is there a way of identifying the flow and return on the kickspace nothing in the manual.