problem with Truma gas boiler

[simon_374337070]

Hi,

I have a 1994 motorhome fitted with a 1993 Truma Boiler for heating the water, the problem is, I have a constant green light on the control panel, I have the temerature dial on full to 70, yet the water only ever heats to about 15 degrees...., however, I took the control box apart, put it back together, and the heater worked, I got piping hot water, turned it off, then on again, and it will only heat to 15 degrees, I could leave it on for 2 or 3 hours and it won't get any hotter.

any ideas?

Simon

 

[SteveW77]

Get in touch with Gary at Arc Systems.he will put you right.

 

[gary]

I got this question in an email and now I know why Steve! where does it say I'm an expert in Trauma water heaters??

First 15C is room temperature so unless your sure the boilers actually fired up, I suspect it isn't and this is simple the water warming up in the tank.

From whats said the heater is obviously capable of working as it has got the water hot once, so the problem is going to be fairly simple.

You don't say if the control switch has two or three lights, two is green for on and red for fail, three is the same but amber for lit. So you should have green or green and amber while it tries to light and green and red if it fails to light after 10 seconds. If you just get green on both systems then it's not working on the three light system and not working on the two light system if the water does not get hot.

Connections are going to be the prime candidate so go though these again while it's switched on and see if it bursts into life but keep the gas bottle turned off while your testing.

Three light control switches, (not sure about two's), have a resistor on the pcb next to the on/off switch, check this has not overheated and damaged it's solder connections to the pcb.

See how you go

 

[gary]

I got this question in an email and now I know why Steve! where does it say I'm an expert in Trauma water heaters??

First 15C is room temperature so unless your sure the boilers actually fired up, I suspect it isn't and this is simple the water warming up in the tank.

From whats said the heater is obviously capable of working as it has got the water hot once, so the problem is going to be fairly simple.

You don't say if the control switch has two or three lights, two is green for on and red for fail, three is the same but amber for lit. So you should have green or green and amber while it tries to light and green and red if it fails to light after 10 seconds. If you just get green on both systems then it's not working on the three light system and not working on the two light system if the water does not get hot.

Connections are going to be the prime candidate so go though these again while it's switched on and see if it bursts into life but keep the gas bottle turned off while your testing.

Three light control switches, (not sure about two's), have a resistor on the pcb next to the on/off switch, check this has not overheated and damaged it's solder connections to the pcb.

See how you go

You will hear things happening hence you don't need the gas on, while trying to light, you will hear a 'clunk' as the gas valve opens and a faint tick of the spark and it's clearer to hear ouside. As theres no gas it should fail, shut down and show the red light. If it does this several times then you can be fairly sure you have found the fault and try it with gas.

Remember though if it's all new to you and particularly if you don't know the history, then you should get the whole system checked over for safety by an expert

 

[simon_374337070]

You will hear things happening hence you don't need the gas on, while trying to light, you will hear a 'clunk' as the gas valve opens and a faint tick of the spark and it's clearer to hear ouside. As theres no gas it should fail, shut down and show the red light. If it does this several times then you can be fairly sure you have found the fault and try it with gas.

Remember though if it's all new to you and particularly if you don't know the history, then you should get the whole system checked over for safety by an expert

Hi,

first, the control has just 2 lights, green and red, it always ignites first time you can hear the boiler kick in and the green light stays on (goes to red if I turn the gas supply off), as for room temperature of 15 degrees, the motorhome is much colder than that when testing, and the water from the cold tap is ice cold, the water from the hot tap is at about 15 degrees, could it be a faulty thermostat???, maybe the dial on the control panel?

Simon

 

[colin-yorkshire]

hi simon

does it work on electic ok

 

[simon_374337070]

Hello Colin,

this is a gas only boiler, it does not have the electric element, it would be great if it did, I was tempted on fitting the electric Truma Therme yesterday so we can have hot water on our next trip starting Sunday, but decided against it. I am hoping I can sort this problem out.

Simon

 

[Damian]

Hello Simon,

The ultrastore has only 2 lights to worry about.

When you first switch it on the green light should light, you should hear a clunk as the gas valve opens, then rapid ticking as the spark ingnitor attempts to light the gas supply.

If there is a malfunction on start, the light will go red and shut down the boiler.

You say the green light stays on, which would indicate that the start process has been successful,have you actually been outside and felt if hot air is being discharged from the flue?

Presuming no hot discharge is present the there is a fault either on the PCB or the water temperature sensors or the ignition.

There are various tests to determine what is causing the problem, but you will need a Truma engineer to sort it out

 

[simon_374337070]

yes, you can feel warm air coming from the externa; vent when the gas boiler is on and the light is green, but as I said, the water is only at about 15 degrees no matter on where you turn the control dial to.

simon

 

[Damian]

Hi Simon, from your reply it would seem that the temperature sensor has failed and as it is part of a loom setup it will mean replacing both.

This requires the whole unit to be removed from the van and stripped to gain access to the sensors and the solenoid valve coil which is also part of the harness.

This is not a job to be undertaken lightly.