Viessmann WB1B 13kw

[dilalio]

Open vent please.

Then you don't need an EV or PRV or filling loop or discharge pipework.

You're filling and venting the CH system via the feed and expansion tank!

 

[dilalio]

If its just a single heating zone, you won't even need a motorised valve!

 

[desktop987456]

If its just a single heating zone, you won't even need a motorised valve!

Correct but since it is coming with boiler, I'll keep it for future in case I decide to put an indirect HW cylinder.

 

[desktop987456]

Then you don't need an EV or PRV or filling loop or discharge pipework.

You're filling and venting the CH system via the feed and expansion tank!

Thanks for your response. This is the bit I am slightly confused, my current system has only feeder tank to maintain the water for CH. I don't have expansion tank installed in my existing system.

 

[desktop987456]

Just confirmed the working pressure at meter for gas boiler from UK should be no problem. Here we use 8" water column pressure = 20mbar

 

[ianmcd]

Thanks for your response. This is the bit I am slightly confused, my current system has only feeder tank to maintain the water for CH. I don't have expansion tank installed in my existing system.

The feeder tank as you call it is the expansion tank, called F&E tank feed &Expansion

 

[dilalio]

Thanks for your response. This is the bit I am slightly confused, my current system has only feeder tank to maintain the water for CH. I don't have expansion tank installed in my existing system.

Ah! This is why you think you need an expansion vessel!

With an OV system, you don't!

The feeder tank also allows for expansion when the water is heated.

The water level in it will rise and fall with changes to water volume during heating and cooling.

The float valve within it rarely needs to operate at all, if the system is properly set up.

 

[desktop987456]

The feeder tank (dedicated for boiler) has no inlet for water to come in. The tank has an outlet at the bottom and a pipe has teed into one of the flow pipe to maintain water level. I keep checking and add water into it manually if the tank is low on water. It gets low occasionally after a month if there is a leak or air in the system.

There is no separate vent pipe from boiler going into the tank (see attached picture). You may laugh at what I have compared to UK standards but I am learning and making improvements based on how much or what I can afford. It is an inefficient system and by installing a condensing I should be able to save on gas. Once CH work out to meet my objective, I plan to put DHW on another heating circuit for my needs.

I always thought there is a non return valve fitted into it and water can only go one way (towards boiler) and it cannot take back water from boiler but I did not understand it. So it is an old school expanson tank with no diagphram inside and water level is maintained due to simple physics.

 

[dilalio]

We're UK installers.
And can only advise on UK standards.
So, you shouldn't be surprised what advice you get, by posting on here!

 

[desktop987456]

fair enough.