Ignition coil - what's the proper name and where to source?

Hi all,

I took some time out today from putting together my brew rig (see, I worked it in :stuck_out_tongue_winking_eye: ) to have a look at the spa system in the new house we bought. It’s a bosch gas water heater that’s been bastardised by the company selling the control system - they’ve pulled out the stock ignitor pack and replaced it with their own board.

Anyways, it’s looking to me like the ignition coil (transducer of some sort) is bung as the board is powering up, but not generating a spark. As luck would have it, I live around the corner from the development shop that made the boards. Apparently the boards are obsolete, but they could supply me with a circuit diagram, just not a parts list.

I’m trying to identify the coil that generates the spark to source a replacement. On the diagram it’s listed as TF2: TC-052614. There are no identifying markings on the physical component.

Can someone tell me what search string I should be looking for? “Ignition coil” just gets me heaps of car sites. Also, if someone has an idea of a replacement part, that’d be great. In the photo, the red cable out the centre goes off to the spark gap.

Thanks for your time!

PFS04RV.pdf (126 KB)

PFS04RV…pdf (38.2 KB)

Sorry, I should mention - I've just spent all day driving around, showing off the board to gas fitters and pool shops and have hit the point of exasperation (hence why I'm coming here). If someone can help, I'd rather spend the time fixing the board than spending thousands on replacing the thing just after we bought the house.

Does it actually have a coil? Or just an element that gets red hot, with a sensor nearby that lets the gas valve know that element is hot before the valve will open?

Post the schematic, that will help.

It should have a coil - it's definitely spark driven (there's the flame sensor and an electrode with suitable gap to the burner). It was a standard bosch hot water service, the company has just added their own control and ignition boards to interface with their airswitch control unit..

The schematic is included in my original post, just above the picture. That's all the info I've been able to muster on it. It's quite disheartening having just purchased our first home, only to find the spa heater might need replacing.

That HV & control module looks very similar to the module I had to replace in my home's central forced air heater. Now a days always on gas pilot lights are not very popular, most built in the last 20 years use instead a module to start the main burners on demand by generating a spark gap at the burner's pilot. Mine had a intermittent problem where it wouldn't spark at time, other times it would. The furnace had a schematic drawing of the heater and it showed the inputs and output of the HV module. I was able to do a little googling around and found that there is a independent replacement market for universal HV module that will replace many models of manufactures modules. Once I had a 'generic' part number I was able to find a vendor on E-bay that sold me a new replacement module for around $50 or so. That was much better then the heater OEM that quoted me $175.

Anyway it's a pretty simple module, mine excepted 24vac as power input, had thermostat contact inputs for initiating a spark and a thermocouple mv feedback signal from the main gas burners to turn off the sparking once the main jets had fired up. It also had a couple of relays to control the main air blower motor and something else I forget, and some safety interlock inputs for hi-temp conditions, etc.

So this long story was just to let you know that if you can locate a local independent appliance repair center, you might have luck finding a replacement module. Or do like I did and google the manufacturer's name and whatever part or model number you might find on the module and see what hits you get, that's where I hit on various universal replacement models that listed being compatible with various manufacturer's modules.

Lefty

Thanks guys for your input. Retrolefty - you words were an inspiration. After I read what you wrote, I sat and thought long and hard about just what the module does and realised... d'oh - it matches your description perfectly and, in fact, there's nothing special about it. What I assumed in a panic - that the module was a custom job - was actually just an aftermarket universal controller.

Just found some matches at fenwalcontrols.com

gorbs: Thanks guys for your input. Retrolefty - you words were an inspiration. After I read what you wrote, I sat and thought long and hard about just what the module does and realised... d'oh - it matches your description perfectly and, in fact, there's nothing special about it. What I assumed in a panic - that the module was a custom job - was actually just an aftermarket universal controller.

Just found some matches at fenwalcontrols.com

Great, glad I was help. The Internet can sure be a powerful problem solver if one doesn't panic and take the time to do a little detective work.

Lefty

Nice one Lefty! Will keep that in mind!