Baxi heating Engineer

[ford34/2]

Baxi 80, condensing boiler, water overfowing out from bottom of Boiler case housing
My Daughter bit the bullet and had the engineer out, Heat Team service,His first call -diagnosed a faulty Condenser right up the top of the boiler, returned 4 days later to repair/replace, big job-4 hours.
Now, when the programmer and the thermostat are shouting for heat the boiler fires up and runs till the CH water is up to boiler temperature, when it shuts down the CH pump shuts down as well, the effect is almost as soon as the rads get a bit heat the pump stops and they cool down again.
My question is -- should the CH pump not run continuosly as long as the the programmer and Room thermostat are asking for heat.
when the boiler detects the water cooling down it fires up and the pump runs again till the next time it senses hot water in the CH system.Then shuts boiler and pump down.
Regards
Stan

 

[mike os]

correct if the heating is on & stat is on then heat is on...& pump runs

not been reconnected right by the sounds of it

 

[clueless77]

get them back out, the repair should be guaranteed. sounds more like water got on a sensor or pcb.

 

[pedrobedro]

Shouldn't the room thermostat operate the pump separate from everything else?

 

[clueless77]

isn't a baxi 80 a combi?

 

[ford34/2]

Room Thermostat

yes, correct when the boiler is running the pump is running.

if you crack the room stat down to "not wanting heat" the CH pump shuts down at the boiler, and eventually the boiler, eliminated the domestic side of the electric circuit as being ok, EG programmer and thermostst, seems to be definatly all connected to the boiler electrics.

Thanks for you time and replies

Stan

 

[the snooper]

dont know if you already have them but here is the link to the baxi 80e instructions including wiring

 

[BIGMIKE]

Pump is wired straight from pcb so that decides when to run it. First thing would be to get them back as you've paid for a repair, but if not I'd link out room stat and clock to make sure there working ok. After that your probably looking at a problem with primary thermistor or pcb.
Mike

 

[M4RKE]

Does this boiler have a pump overun built in as many of the new boilers have these fited to stop them from ketling ?

 

[tigler]

Was just about to mention the pump overun stat or sensor. This activates whenever the boiler has reached a pre-set temp after running for a while so that the heat in the system is circulated after the boiler cuts out for better efficiency.

 

[ford34/2]

Thank you

Thanks guys, Daughter been trying to get through to Baxi service team all day- always engaged, she will put it back into their hands to try and fix, it was ok before they came to fix the "condenser" right up the top of the boiler, thats what service man called it.
Again thanks every one for their input.
hopefully I will update with good news-- in due course.
Stan

 

[jono49]

Baxi

I take it this "Combi" is GAS fuel! Even so if it's a Combi it will have a expansion vessel and a Guage for water pressure and a Mark on it showing 1 bar thats the mark your actual pressure should be for a two story house 0.5 bar for a single story! if the pressure has dropped off thats why it stops before the RADS get hot as it cant circulate it properly and the boiler reaches the Temp first! or the boiler could be airlocked if he has drained the system today? When it stops do you have to reset anything like a lockout button????

 

[the snooper]

our boiler wont even fire up at all if the pressure is down pump works but the boiler wont ignite

 

[jono49]

They usually are protected! but got to ask questions to make headway!

 

[the snooper]

i like the good old multipoint if those went wrong it was usually the diaphragm

 

[ford34/2]

I take it this "Combi" is GAS fuel! Even so if it's a Combi it will have a expansion vessel and a Guage for water pressure and a Mark on it showing 1 bar thats the mark your actual pressure should be for a two story house 0.5 bar for a single story! if the pressure has dropped off thats why it stops before the RADS get hot as it cant circulate it properly and the boiler reaches the Temp first! or the boiler could be airlocked if he has drained the system today? When it stops do you have to reset anything like a lockout button????




Pressure in the system is in the middle of the green, about where it has always been . The boiler fires up runs for 5+ mins etc, I`m guessing when it reaches operating teperature, or is it when the water in the system is sensed to be at the temperature on the CH temp rotary pot, it shuts down and the CH circulating pump shuts down as well. as the boiler is hot I`m guessing the water in it stays hotter longer than that in the system, the Rads are just getting a bit heat into them when the boiler and the CH pump stop, before the boiler stat shouts for more heat the rads are loosing heat. She has had no lock outs, no combination of flashing LEDS etc, so NO resets at all. the boiler fires up when the boiler stat is shouting for heat. The room Stat is set high in an effort to persuade the system to get hot, and the programmer is on timed. She has been selecting to constant when she has come in from work.
but whatever the programmer is on, even a boost for the one hour, it doesnt effect the boiler and pump shutting down togetherwhen the boiler itself is up to its temperature.
She`ll try Baxi again tomorrow.
Stan.

 

[jono49]

I would have thought having the room stat high would defeat the object! as heat rises and satisfying the stat quicker!!

 

[the snooper]

having the room stat high only means the room has to be even hotter to switch the system off they are only a basic on off switch

 

[ford34/2]

Missleading

The "room" stat is actually in the hall way, its making/ breaking contact at about 14 degrees, it will go up to 30 degrees which would be impossible for the hall way to ever get that hot, if she was to put several rediators in I still doubt if the efficiency of the boiler would raise the background hall way temperature to anywhere near approaching 20/22 degrees.

even when the boiler and the CH pump has shut down, by rotating the knob on the hall "room"thermostat you can hear the click of the thermostat at whatever the hallway temp is currently at,
if the boiler is running and making heat, if you reduce the thermostat temp in the hall way, the boiler closes down as it thinks the background temp is up to requested heat.
I am convinced it is not the programmer or the room thermostat.
If either were faulty why would the boiler fire up at any requested time in the first place?? and why would the room stat switch the boiler on and off at whatever the room temp it is at, at that given moment.
The room stat has been set up to about 25 degrees which to me means the boiler should be producing heat for whatever period of time the programmer requests it too.
The CH circulating pump should be running continously as long as the programmer and the Room stat shout for heat.
The boiler should start/stop whenever the boiler itself reaches its own designated operating temperature for as long as the programmer requests it too.
If in the unlikly event the hallway reaches the temperature set on the "room" thermostat it will shut the Boiler and the CH pump off till the hallway temp drops and the thermostat cuts back in,thats providing the programmer is still requesting the boiler to run when it cuts back in.
Stan

 

[the snooper]

here is my under standing of this a baxi 80e which is not a condensing boiler
right up at the top is the heat exchanger for the central heating so this is what the engineer had dealings with.
it could be possible that the engineer has some how restricted the flow through the heat exchanger which causes the central heating temperature sensor to shut down the boiler because of over heating.
domestic hot water uses a separate heat exchanger and temp sensor so remains unafected. see pictures below