Help, I can't identify this system

[marios_kin]

I hope someone out there has some answers, because this has stumped me.

Firstly we have a 'not new' potterton standard wall mounted boiler, this supplies heat to a non standard indirect combi cylinder (it has 1 extra water connection to the lower third of the cylinder). The heating is a sealed system, with no visible means of filling and no visible expansion vessel. The heating side for cylinder and c/h looks pretty standard with pump, a 3 port motorized valve and a relief pipe between flow and return, as expected.

Now is the confusing bit. The cold feed to the storage tank comes up as a 22mm feed, it tees off to a tee shaped 'valve', before continuing up to another tee into the cylinder, then on to a small pressure vessel (about 150 x 100 mm), then reduces to 15mm to feed the ball valve at the top. The hot water supply from the cylinder is normal (if lower than expected), 22mm, however as it goes down it comes to this tee shaped 'valve'. All the connections to this are 28mm reduced to 22, the pipes then continue on to taps etc.

It appears to be able to fill the heating circuit within the cylinder but I have never come across one like it before. I have been asked to fit a towel rail in place of the bathroom rad and trv's to the upstairs but am not prepared to start until I am confident of getting it going again. Help me please anyone who is familiar with a system like this.

 

[corgiman]

can you take a piccie as i really cant get my head around your description?

 

[croydoncorgi]

Maybe you're looking at some sort of heatstore / unvented HW system?.....
In which case you may need a licence to work on it.

 

[marios_kin]

You could be right Croydon but until I have Identified the system I cant be sure, so I shall burn that bridge if I get to it.

HI Corgiman I have sent an email to admin with a piccy I did from 'Paint', cant get a photo of it without taking the airing cupboard apart, (its one of that type), dont think I will be doing any work on the cylinder!!!!

 

[DIYnot]

Picture from marioskin:

Picture

 

[marios_kin]

does anyone know about this system, it is a vented dhw but seems to be a sealed heating circuit. I seek advice on how it is filled and how pressure is regulated, with no visible means of regulation, pressure gauge or safety valve.

Alternatively I seek somewhere that may show the relevant information.

Even if I am unable to work on it, I am interested in finding out about it just for the hell of it.

Thanks guys

 

[marios_kin]

I have been unable to find anyone who would know this type of system and made an offer to replace it with a conventional indirect cylinder and header tanks. Should be cheaper for them in the long run.

 

[DP]

Three port valve on the left is either a diverter or a midposition valve. Bottom connection most likely goes to radiator zone. Gate valve will be the bypass for the primary flow.

Right hand side is mains water related. Pressure vessel will be for water hammer arrestment. Ballovalve is for isolation of cold water inlet to boiler. Valve? is a mixing valve to give a preset heat of hot water for the hot taps.

Upper section of the cylinder is F&E for the cylinder which is essentially a heat store. Three posrt valve is likely to be a diverter instead of midposition.

Then, I could be wrong.

 

[marios_kin]

Thanks DP. I spent nearly an hour at the place and sussed all that, the mixer valve did throw me, as its the first one I have come across. Another plumber I spoke to thinks its a strange place to have one as it would cool the water, even to the sink, where you need hot, hot water. However, I could find no visible means of filling the heating circuit, there is no apparent safety or pressure relief valve or any signs of a pressure gauge, even tho the system appears to be a sealed heating system with a standard type wall mounted boiler. The other thing I did notice was the 'extra' cold supply pipe going into the cylinder, where normaly DHW is stored.

I have since been told that it probably has a PV in the back of the boiler. If that is the case then there may be some forms of safety devices in there as well but the only pipe work to the boiler itself is the flow and return, and gas supply of course.

Now I just wished I could find out who did the installation on the estate. At least that way I will feel I have done my job and pass the buck.

Cheers

 

[brumylad]

looks like a thermal store system, becoming more common in new build. Have a look at the albion site.
http://www.albion-online.co.uk/mainsflow x.html

 

[marios_kin]

Thanks Brumy, thats brilliant, nail right on the head.
And thanks DP your description now makes a whole lot of sense to me now.