Viessmann combined PRV and condensate pipe

[Alfie25]

On most boilers I've seen, the PRV is routed through the outside wall and then back on itself, so if ever the boiler discharges any water via the PRV then you can see it.

The Viessmann range seem to combine the PRV and the condensate pipe into one, so how are you supposed to see if the PRV is discharging ? It seems you can install a tundish in the condensate pipe, but again, how can you differentiate. Also, unless you like a water feature in your house, why would you want a tundish on an internally routed visible condensate pipe that is constantly discharging whilst condensing?

 

[Dan Robinson]

Atag do the same and there is a clear tube of the PRV side.

 

[JBPHS]

Do the Atags still leak where the tube connects onto the outlet of the PRV when it has been operated?

I must admit that some tundish's are appalling, they do nothing but direct the flow out of the sides.

A leaking PRV as opposed to the condensate running, can be identified quite easily (I.e. Running condensate does not cause system pressure loss unless the primary heat exchanger has packed in). It can be proved physically in much the same way as a leaking Expansion Valve or T&PRV on an unvented system can be found.

James.

 

[Dan Robinson]

Not noticed it on my installations but then their PRVs don't blow

 

[dreadnoughtheating]

On the more common 100 (domestic range), it is the WB1 'c' range (been on the UK market for some 12 moths only) that has the combined PRV/Condensate drain. (system and Combi types)

As per Dan, this is a reliable boiler, not seen any letting by on my installs (around 20 or so, mostly WB1'B')

DH

 

[Phill Peck]

If the prv is passing you'll run out of pressure quite simple really.

As a homeowner that is all u need to know.

As a gas engineer you'll figure out how to see if the prv is actually dripping