Boiler not firing up…

Worcester combis only have one 230v switch wire coming on to RT on the PCB. To rule out your external controls you link out from the 230v out terminal to RT to permanently call for heat.

Hot water runs off the flow sensor on the hot feed.

If you call for heat on the nest and are getting 230v to RT then the fault is on the PCB. It's either on or it's not.

That's the usual process from the external controls side of things. However, the hub should be next to the boiler anyway and easy enough to check? I'm not sure what wires he's looking at because a nest really should just be flexed from the combi or the wiring station.
 
lewism said:
Worcester combis only have one 230v switch wire coming on to RT on the PCB. To rule out your external controls you link out from the 230v out terminal to RT to permanently call for heat.

Hot water runs off the flow sensor on the hot feed.

If you call for heat on the nest and are getting 230v to RT then the fault is on the PCB. It's either on or it's not.

That's the usual process from the external controls side of things. However, the hub should be next to the boiler anyway and easy enough to check? I'm not sure what wires he's looking at because a nest really should just be flexed from the combi or the wiring station.
Click to expand...

So im hoping it is a fault on the pcb
Because if the wire is damaged he’ll need to rerun that one wire

when he was looking he called out that one wire which he said should be live but couldnt get any live out of it

what does RT mean btw?

i guess if i was fixing this id rerun that cable temporarily then check everything works… before fixing in place permanently

got real lucky that the weather temp picked up here and is isnt that cold
 
I was thinking it’d be pretty cool
If the new wire could be dragged through the floor by being tied up on one side with the suspected faulty wire and pulled across

its about 3/4 metres across
But guess the problem is this method could damage other wires that r working
 
psd99 said:
I was thinking it’d be pretty cool
If the new wire could be dragged through the floor by being tied up on one side with the suspected faulty wire and pulled across

its about 3/4 metres across
But guess the problem is this method could damage other wires that r working
Click to expand...

If you have diverter valves then it's not a combi, it'll be an S Plan or a Y Plan which means there will be a wiring centre next to the two zone valves and you'll also have a hot water tank.

RT is just call for heat. It tells the boiler to fire up. The controls (thermostat's) are what turns RT on or not.
 
We don't know whether it's a combi or not.
They can be fitted with motorised valves, for zoned heating, and even be connected to a hot water cylinder.
Also, RT is for Vaillant/ Glowworm boilers.
WB use : LS, NS, LR, & their combi boilers can take TWO SWL from a Nest or HIVE etc to control the preheat.

Merry Christmas :D
 
FlyingFish said:
We don't know whether it's a combi or not.
They can be fitted with motorised valves, for zoned heating, and even be connected to a hot water cylinder.
Also, RT is for Vaillant/ Glowworm boilers.
WB use : LS, NS, LR, & their combi boilers can take TWO SWL from a Nest or HIVE etc to control the preheat.

Merry Christmas :D
Click to expand...

merry christmas mate
I remember when the system was being installed took the team hours to get the wiring right.

this aint a combi
System boiler (i believe) with a megaflow

Good job that otherwise hot water would have been a problem last couple of days
 
FlyingFish said:
We don't know whether it's a combi or not.
They can be fitted with motorised valves, for zoned heating, and even be connected to a hot water cylinder.
Also, RT is for Vaillant/ Glowworm boilers.
WB use : LS, NS, LR, & their combi boilers can take TWO SWL from a Nest or HIVE etc to control the preheat.

Merry Christmas :D
Click to expand...

LS/LR/RT, 6 and half a dozen. It's a call for heat, doesn't matter how many zones there are.

I think out of the thousands of boilers I've wired up I've seen maybe half a dozen combis with zoned heating due to wet under floor heating.
 
lewism said:
Worcester combis only have one 230v switch wire coming on to RT on the PCB. To rule out your external controls you link out from the 230v out terminal to RT to permanently call for heat.

Hot water runs off the flow sensor on the hot feed.

If you call for heat on the nest and are getting 230v to RT then the fault is on the PCB. It's either on or it's not.

That's the usual process from the external controls side of things. However, the hub should be next to the boiler anyway and easy enough to check? I'm not sure what wires he's looking at because a nest really should just be flexed from the combi or the wiring station.
Click to expand...

he has an ri

if you know your stuff you know thats not a combi :o
 
so all fixed now, thank god. no cables replaced at the end.

Still couldn't work the exact issue total mystery, plumber no1 seemed to have mis diagnosed the whole issue.

but one of the diverter valves was faulty as the movement on there was far too free, I got that replaced along with the magna clean which was held in place using teflon tape smh

one obersation now is that the Hot water is way too hot though, how often do the thermostats on a megaflow need to be replaced?
 
Not often, and if there was an over heat scenario there is a safety thermostat to break the chain, and that requires a manual reset.
Do bare in mind though, UVHW cylinder stats are set to 60C, which is quite hot. (To stop leagionella) So just because it's hot, don't think it's wrong ;)
 
FlyingFish said:
Not often, and if there was an over heat scenario there is a safety thermostat to break the chain, and that requires a manual reset.
Do bare in mind though, UVHW cylinder stats are set to 60C, which is quite hot. (To stop leagionella) So just because it's hot, don't think it's wrong ;)
Click to expand...


yes im sure when the plumber visited he turned that thermostat down, but having said that 60C is a crazy temp man!

kids could get scalded do u think having it that high make a diff in exactly how much hot water is stored in the tank? Also isn't there an argument that the hotter the water the more energy is getting used up
 
It's part of regulations. And yes there are temperature bands in a normal cylinder, (hotter at the top, check your boiler thermostat is set to just under 70C) and yes the thermostat is in one location on the cylinder. And yes you cant hold your hands under that sort of temperature ;)
If it was in a location with vulnerable people, then you can have a thermostatic blending valve fitted to regulate the output temperature, but for normal domestic use, we are left to put up with it :D

If you want to lower it you can, it's your house your choice m8.
 
FlyingFish said:
It's part of regulations. And yes there are temperature bands in a normal cylinder, (hotter at the top, check your boiler thermostat is set to just under 70C) and yes the thermostat is in one location on the cylinder. And yes you cant hold your hands under that sort of temperature ;)
If it was in a location with vulnerable people, then you can have a thermostatic blending valve fitted to regulate the output temperature, but for normal domestic use, we are left to put up with it :D

If you want to lower it you can, it's your house your choice m8.
Click to expand...

I will have a look later on to see what it is actually set at, the boiler heating temp is actually 65C.
 
That's good enough, you should be able to reach 60C at the cylinder with that, so long as its not set to send 80C to the cylinder, which would be a bit excessive, and cause a hotter temperature at the top of the cylinder (where dhw is drawn from).
 
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