Combi Boiler Question

[waddycall]

More than likely pump overrun through internal or external bypass.

 

[gaz1]

Not if it's a Viessmann, but it's irrelevant dissipating the heat soak remains the same, how is it done @gaz1 ?

the make also has the same problems with a diverter valve

most boilers throw over the diverter valve and start the pump for a second to bleed off that hot side within the heat exchanger

hence why most boilers have both heat exchanger and diverter valves on them

if that diverter valve is sticking upon opening you get a twin flow one side pushes within the central heating side heating the nearest radiator whilst you run your hot tap

the central heating side either runs or not but when it does you can gain high pressure down the hot tap

to make it very clear and by the google search as its a common problem

Google Search

 

[reb78]

You might have said, but why don't you just turn off the valves at the rads that are in the way, drain and remove them and leave the rest of the system untouched. Then when ready drain the system, alter the pipes as needed for the replacements and refill - could be done fairly quickly and only a few hours downtime.

 

[Craig-SM]

You might have said, but why don't you just turn off the valves at the rads that are in the way, drain and remove them and leave the rest of the system untouched. Then when ready drain the system, alter the pipes as needed for the replacements and refill - could be done fairly quickly and only a few hours downtime.

The pipe work runs from under a cabinet along a long run of skirting board before dropping level with the top of the tiled floor and back up again. There is a lot of work to sort out first for the pipe work, flooring, woodwork and walls before refitting a new radiator. I’ll cap it under the cabinet and refill the system until it’s ready to be fitted.

 

[gaz1]

if people used gate valves for upstairs / downstairs you could actually leave the upstairs still full of water and just drain downstairs but plumbers are skinflints for themselves

i also use 2 gate valve for draining the system as its alot faster to drain the system

me personally if your draining it down its up to you if you just want to fasten 2 gate valves onto the system

then when its needed just open the valves top up the system and bleed it and then theres no draining of the system again

dont use stop taps but you could use ball valves but they do leak after a while

 

[dholdi]

I don't understand the point you're making?
The question wasn't how many hx are in the boiler, but how does the boiler deal with the heat soke of running a hot water tap.

Your first post stated there is only 1 hx, combis have 2.
You then went on to say Viessmann dont but they do.
A number of people including me have said what happens when the hot tap is turned off

 

[Jaeger_S2k]

Your first post stated there is only 1 hx, combis have 2.
You then went on to say Viessmann dont but they do.
A number of people including me have said what happens when the hot tap is turned off

I haven't the energy to compete.

 

[dholdi]

It wasnt a competition, you said you didnt understand so I explained