Caveat emptor?

[ban-all-sheds]

 

[ericmark]

I use a Myson but not the kick space

version. So I will let the buyer be aware of a problem with the Myson with modern central heating. It has no water valve. It worked well with the older system, hot water could circulate as many times as it liked all the boiler did was monitor temperature of the water leaving the boiler it did not matter if hot water was returned to boiler it did not affect the boiler. So having radiators in parallel the only problem was to ensure using the lock shield valves water goes through every radiator.

However for the boiler to extract the latent heat of evaporation the return water must be cool, so the modern boiler both measures output and input temperature. Once the input temperature starts to rise then then boiler starts to reduce flame size. With standard radiator using a TRV in parallel with a by-pass valve this works well and with the anti-cycle software fitted in boiler it means no need for a room thermostat the TRV will control each room.

However to work with a Myson the plumbing needs to be in series not parallel. You can't mix and match. Hot water goes through each radiator and if pipes are hot and room needs heat then fan starts, so each Myson will blow hot air as required and the return temperature of water will reflect how many fans are running, no need for a by-pass valve as water is never restricted.

I suppose there could be a way to include a TRV on a Myson system? But my enquires last time I looked did not show any control on water flow. There is also a problem with heating and cooling times. I had to fit a radiator as well as Myson as within minutes of the boiler turning off the room was cold. There is no stored heat in the Myson very economic in that heat up time and cool down times are fast and with a house with all Myson type radiators and a boiler which alters its flame hight it would work very well. Ideal for offices and shops where heat up and cool down times being short can really save money. And no space required to fit the heaters.

However although not what one would call noisy I do find at night when TV sound level is set low so as not to upset neighbours as Myson kicks in I have to raise TV sound level. So in the bed room they could wake one as they kick in.

With a large system I am sure one small Myson would work OK in parallel, Our Myson is I think around 4 kW output which is a major hunk of the boilers output of 25 kW as a result I have not moved to using a condensate boiler although looking at ways to modify the Myson so it can control water. What it needs is a motorised valve with a by-pass so enough water flows to activate the water temperature switch and as fan kicks in the valve opens giving the extra flow required. But the speed control would need doing away with. At the moment two controls temperature and fan speed the latter controls output.

I do question the idea of having controls i.e. switches at foot level. I would have thought these should be remote from unit as hardly kick proof. Having foot operated switches could be another option but they hardly seem man enough for kicking on and off?

 

[SimonH2]

It has no water valve.

Indeed.
Where I used to work, we had a few of their wall-mount models in the office. Great in terms of heat output for a small amount of wall space - but not good from the POV of control.
I had them all plumbed with an electro-hydraulic valve* on the feed, which was wired to the controllers used by the aircon (cooling) system. In hindsight I'd have suggested just using twin-coil aircon units mounted lower down (think something similar in size to an electric storage heater, but internally it's just a bigger version of the unit you provided a picture of).

When heating was called for, the controller would open the hot water feed, the coild would heat up, and the internal pipe stat would turn on the fan. When switched off, the hot water flow would stop, and when the coil cooled off, the pipe stat would stop the fan.

* More or less the same (or similar) valve body as a TRV, but the control head is electrically operated rather than sensing air temperature.
These weren't the ones we used (ours were Honeywell), but do the same job. They take a while to open and close, so ideally you want a thermostat with very little hysteresis - that way the valve will "sort of modulate" rather than heating the room up, letting it go cool, heat it up again, ...

There was a lot wrong with the system as a whole - but I wasn't allow to fix it, they just kept getting different (so called) "heating engineers" in who would add bodges to the bodges done by the previous outfit.