What central heating/hot water system do I have?

[a4007035]

Hi,

I have recently moved house (to Ireland). I had a pretty simple combi boiler system in the UK.

Now I've got this system as per the pics which I don't exactly understand what system I have or how it works. So many taps connected to the pipework - not sure which pipe is for what.

The boiler is a Vokera Mynute 30HE.

 

[ianmcd]

You have a sealed system with S plan 2 zone heating and an indirect Hot water cylinder controlled by a mechanical thermostat

 

[fixitflav]

The phial hanging on the end of a capillary in pics 2 and 4 isn't doing anything, and the capillary appears to be cut off, so my guess is the valve to the cylinder isn't doing anything either. And there's no electrics to tell the boiier to fire on low cylinder temperature. Might be worth adding a strap-on cylinder stat, and modify the system wiring to suit.

 

[CBW]

“Taps” are gate valves for isolation purposes, but can be prone to snapping if used incorrectly, or wear/tear.

 

[a4007035]

Ok thanks for the replies.
1. Is it worth moving to a combi boiler system? We just got the boiler serviced and the guy advised that the heat exchanger needs changing. Vokera are charging €400. The engineer advised that the boiler isn't the best. And I also saw on which.co.uk that vokera boilers aren't the best.

2. The central heating is fine and the rads are working on. However the hot water coming out of the taps is about 45C. We have mixer taps and I would have expected that if the tap is all the way to hot that it would be a lot hotter. Is there a way of making it hotter? Do I need to? Is there a risk of legionnaires disease? I thought it would had to be above 55C or something like that.

 

[CBW]

I don’t think the heat exchanger being blocked would stop it coming out at 45 degrees. More likely that your temperature control on the cylinder will be set too low, try it on 60 degrees. It looks like it’s being controlled by a trv head?

 

[fixitflav]

Ok thanks for the replies.
1. Is it worth moving to a combi boiler system? We just got the boiler serviced and the guy advised that the heat exchanger needs changing. Vokera are charging €400. The engineer advised that the boiler isn't the best. And I also saw on which.co.uk that vokera boilers aren't the best.

2. The central heating is fine and the rads are working on. However the hot water coming out of the taps is about 45C. We have mixer taps and I would have expected that if the tap is all the way to hot that it would be a lot hotter. Is there a way of making it hotter? Do I need to? Is there a risk of legionnaires disease? I thought it would had to be above 55C or something like that.

Following on from #3, my guess is the cylinder is only heated by accident when CH is on, there's nothing to tell the boiler to fire for HW. You could change the valve with the capillary to a motorised valve, add a cylinder stat, and wire it to suit.
Can't tell from here if there's anything wrong with the boiler, but if it works OK I would leave it alone for now. If it does fail, as the other kit is in place I'd just replace it with like for like, not change to a combi

 

[ianmcd]

The temp of the water in the HW Cylinder ,will be whatever the temp is set on the gas boiler, your mixer taps must be set at 45 degrees

 

[ianmcd]

I don’t think the heat exchanger being blocked would stop it coming out at 45 degrees. More likely that your temperature control on the cylinder will be set too low, try it on 60 degrees. It looks like it’s being controlled by a trv head?

@Chris_W that is a mechanical cylinder stat, if you look closer you will see the sensing Phail that has been removed for some reason, that phail senses the temp of the cylinder and closes the valve just like a TRV, up here they are referred to as RAVI stats, but think that was one of the makers back when they were common place

 

[CBW]

if you look closer you will see the sensing Phail that has been removed for some reason

I wondered what fixitflav was referring to as a phial. I might need an eye test

 

[fixitflav]

@Chris_W that is a mechanical cylinder stat, if you look closer you will see the sensing Phail that has been removed for some reason, that phail senses the temp of the cylinder and closes the valve just like a TRV, up here they are referred to as RAVI stats, but think that was one of the makers back when they were common place

But what tells the boiler HW is called? I suppose if there is a boiler bypass, the boiler could be fired periodically, perhaps manually switched, with both zone valves closed. But you would want the phial to sense cylinder temperature to avoid overheating. The boiler then cycles on control-stat when the mechanical valve closes. But that's not the situation here. Doesn't sound very satisfactory anyway.

 

[ianmcd]

But what tells the boiler HW is called?

Probably just on a timer, cant understand why another zone valve wasnt used

 

[Razor900]

@Chris_W that is a mechanical cylinder stat, if you look closer you will see the sensing Phail that has been removed for some reason, that phail senses the temp of the cylinder and closes the valve just like a TRV, up here they are referred to as RAVI stats, but think that was one of the makers back when they were common place

We call them Tapstats here for the same reason. I think the official term is Cytrol valve though

 

[Madrab]

The engineer advised that the boiler isn't the best. And I also saw on which.co.uk that vokera boilers aren't the best.

I guess it's what is he comparing the boiler too. Vokera aren't the best no, but neither are WB but they and Which claim they are. Vokera are a great boiler, especially if it's been regularly serviced,for their price point. I believe a lot of the other manufacturers aren't and are way overpriced but that's another argument.

I would recommend you get an experienced CH system engineer in to advise what can be done with your current system to update it. Did the engineer that looked at your boiler/system not suggest any upgrades?

What made the engineer think the boiler will need a new HEX?

 

[a4007035]

Thanks for the comments.

I guess it's what is he comparing the boiler too. Vokera aren't the best no, but neither are WB but they and Which claim they are. Vokera are a great boiler, especially if it's been regularly serviced,for their price point. I believe a lot of the other manufacturers aren't and are way overpriced but that's another argument.

I would recommend you get an experienced CH system engineer in to advise what can be done with your current system to update it. Did the engineer that looked at your boiler/system not suggest any upgrades?

What made the engineer think the boiler will need a new HEX?

See his comments on the pic

I've turned up the thermostatic valve to 5 and the hot water is ok.