Hydronic plinth heater advice

[Skoorb]

Hi,

It's another hydronic plinth heater question.

We are having our kitchen redone - it's a kitchen diner that goes the full length of the house, so fairly big. There is only one radiator at the diner end, so the kitchen tends to get a little nippy.

So, we thought, why not put a hydronic plinth heater in the kitchen end? We've picked a spot directly under the boiler, so we can run new pipework straight from the boiler for this one heater, so won't have any flow issues. The new kitchen is going in in March, and we have put a full aerosol of X400 in to clean the system out before we drain and flush to fit the heater. There is a Magnaclean already on the system.

However, there's the debate about whether to go for a Myson or Smiths heater.

I know people say Smiths are more reliable, but has anyone actually had a Myson one break?

I ask becasue the spec sheet shows the Myson one pumping out a lot more heat, and being quieter in normal use, so it looks like the better buy:

Myson 800
Sound level (measured at 2.5m)
Normal: 28.5 dBA
Boost: 49.8 dBA

Motor: 40 watt

Heat output at 50C:
Normal: 1707 watt (5824 Btu/h)
Boost: 2192 watt (7478 Btu/h)


Smiths SS9
Sound level (measure at 1.5m)
Normal: 41 dBA
Boost: 46 dBA

Motor:
Normal: 24 watt
Boost: 35 watt


Heat output at 50C:
Normal: 1100 watt
Boost: 1300 watt
​

Although the Myson noise is measured closer to the unit than the Smiths, the Myson still says it will chuck out way more heat than the Smiths, which is what you want surely?

What do you think? Myson or Smiths? Why are Smiths better if they put out less heat?

I'm looking forward to your advice on this.

Cheers.

 

[John D v2.0]

We have two ss7 and one ss9, the ss7 are virtually inaudible but the 9 is a bit noisy. One of the ss7 is the selv version for bathrooms.
We actually got them to swap out the fan part of the ss9 as it was so bad, and the new one is better, but it's still got a good rumble going on.
We went with Smith's rather than Myson because the smiths can run on 35c water and we have a low design temperature as it's a condensing boiler, but in a standard 50+c system it wouldn't matter so much.

 

[Skoorb]

We went with Smith's rather than Myson because the smiths can run on 35c water and we have a low design temperature as it's a condensing boiler, but in a standard 50+c system it wouldn't matter so much.

Ahh. We have a condensing combi boiler. Do you think the Myson may not be suitable? Myson's datasheet goes down to 30C.

 

[mogget]

If you're running at any normal flow temperature, that is to say that your radiators aren't absolutely massive, either heater will be fine. I presume the spec means 50degreesC flow temperature which is quite low already.

You don't want to overdo the heat, you should do a heat loss calculation for the room. Calculators are available online, don't forget the radiator will provide some of the heat. Please don't use British Thermal Units, they're ancient.

 

[mogget]

Also, I wouldn't trust either decibel figure, sound pressure is usually measured at 1m and drops off very quickly as you get further from the source of the noise, so both figures are a fudge.

 

[Skoorb]

Hey. Thanks for your responses. That's all really useful.

The flow temperature should be fine - we will be putting a whole separate loop on directly from the boiler - it's only a few meters straight down through a floor to where the unit will go.