Top 20 Bosch Aquastar 125B Water Valve Assembly conversion kit - 8707002499 - Page 3 Questions & Answers

Hot water sensor defective

Check the gas valve ,and pcb

Sounds like a flow sensor may be bad. It may be registering flow when there is none and it sending signal to ignitor and gas solenoid that there is.

Sounds like the thermocouple is not holding and dropping the pilot out , so its could be the thermocouple or the valve it connects in to . But you can always contact bosch tech help line they are on line

It may well be a honey well which you can just change the motor . The top cover should come off 1 screw holding it and lift off you should see the motor there . Most plumbing and heating shops will stock replacement motors .

Error Codes and Troubleshooting Bosch Tankless

Check for water leaks on the system also check pressure relief it may be passing water .

Have you bled the rads of air

Davey, look in your manual, I believe it may be auto pilot when unit is switched on. Check the attached links,instruction and guides, Good luck "I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info." Electronic Highflow http://www.bosch-climate.com.au/files/201208020158440.201207160720590.70R_UserManual1023V2_AU.pdf Bosch Installation Manuals

Attached is a link to the pdf format user manual. http://www.bosch-climate.com.au/files/201207160640570.Hydro%20V2.PDF

Contact the local distributor of the product for the exact information you need about installation. If you are on city water you should be fine.

Could be one of three things first the dip tube on the cold side of your water heater could be broken off which would cause the cold water took to come out of the outlet side of the water heater to soon before being heated all the way which can be replced second your water heater could be full of sediment to the point where you're not getting the full amount of hot water so you would need a new water heater and third it could be a bad cartridge in Your Shower depending on the type of valve you have which could cause the water to mix. third one is least likely

People often think it is EO, but it is EC. Depending on the age and instalation, ithe may be a very simple repair. EC is a failure to ignite.

before you condemn the tank, you may want someone to check the venting, if the condensate trap wasn't installed correctly, or at all then this could very well be the source of your moisture!

check that the flue fan is working and that the plastic air tubes from and to it are connected

Can you get the manual online? You have the Manufacturer info so you probably have the model number too. I found a manual on Manuals.com for my boiler so they may have yours too which will hopefully have some information on filling boiler although I realize each installation is somewhat different but that's why it's difficult to answer you question. Usually there is a manual pressure valve that regulates the water pressure in the boiler which is usually pretty low...like less than 20 lbs. The manual should tell you the pressure as well. But this pressure valve has a flip handle that comes off the cold water line to the boiler to do just what you want to do...refill it with water. When refilling the boiler (if you find the valve, you may have to purge the air out of the lines which there is a whole other process for. But you shouldn't allow cold water into a hot boiler...it could crack it when the cold water hits the hot cast iron. So make sure the boiler is cool when filling it up. Now go try to find that manual!

Having problem finding one. Is there a model #? Also what are you trying to find out? as sometime googling the problem finds a solution faster than googling manual.

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The Bosch Hydropower units have poor electrical design, anyway assuming the heater is working properly, I would get it serviced for this that is <(TURN OFF GAS>), backflush water circuit, just unplug in and out water pipes and connect a hose to the outlet its easy enough to find a fitting or something, but you may need to bend the pipes around a little but do not hurt them!, the crud buildup in the pipes will reduce your efficiency like if you use it with unfiltered rain tank water you would want to clean it about every 5 years on the other hand if you have hard water as in bore water then I dont know but I think calcium buildup will be your problem. hard water clogs up everything, disassemble and clean out water inlet manifold, there is a mesh screen in there, on mine it was in bits all through the ports clogging everything up. Now if needed clean over the whole unit with compressed air to spruce it up and reduce fire hazard or if your diy then it's nice to clean things before working on them imo. Don't ask me what all that would cost! You don't need to mess round with the gas side that's all fine. Now here's what you do to fix em, this is for a Bosch Hydropower 10H but I assume it probably applies to the other hydropower models too. Ok for those wanting more information the water flow runs the electronics @ 1.5v DC wich charges the high voltage pilot igniter but it also runs the 2 solenoids for the pilot gas circuit and that pilot circuit operates the diaphragm for the main gas valve. The thing is those 2 little solenoids are grounded through the whole unit, if you look it,s not great, so what I did was add a piece of wire say 5 amp should be heaps, now connect the wire to the fixing point for ground next to the electrical box and now connect the other end to one of the chunky screws that holds on one of the gas solenoids(DON'T REMOVE SOLENOIDS UNLESS YOUR REPLACING THEM THEY ARE VERY FRAGILE AND DON'T ABSOLUTELY DON'T UNSCREW THE SCREWS ON THE LITTLE COLORED PLASTIC BIT, That said I used the green one at the back, don't worry it wont leak gas as long as you only remove one screw but of course (>TURN OFF THE GAS<). Tighten up all the screws, again it doesnt hurt to go over the unit and check all the screws and bolts, there is one screw for calibrating the sliding knob also. And that's it turn on the gas and water and go test your brand new water heater! More info, you can test the generator with a multimeter, just unplug it and test the voltage with the water running through it obviously. Mine was about 1.6v You could also test the resistance of the gas solenoids with and without extra wire, etc. Fyi there is a brass screw about half way up on the left side of the unit facing out that I use to bleed the gas line, at least that's what I use it for. Just unscrew it a bit while its trying to light you just have to flick the switch a few times until the gas comes through then screw it up again. Also it doesn't hurt to go over everything with some soapy water in a sprayer to check for gas leaks especially if unit is old or if you can smell gas, I imagine if there was a gas leak inside the cover that would cause some issues. Anyway you wont believe how well it works after this mod, it ALWAYS starts as long as u have gas, it will stay lit at pretty low flow levels so you can mess round with the cold tap and it wont cut out to a point, I used to just have the cover off cos I was always messing with it trying to get it to light or tuning the knobs man it drove me nuts. Now I just leave it at the mid point between my summer and winter settings. I also disconnected the lights to help it work better but I think that's overkill. You don't really need to blast the hot tap anymore if you have enough flow it will just come on. Oh and if you still need or want to better control the temps then get plumber to install a tempering valve. The flow control knob I just have cracked open but I think If you have not enough pressure at hot tap you could open flow more and also turn up the heat more. P.S. my 10H was about 10yo when I serviced it. The Wizz.

Your electronic ignition unit is not rectifying through the gas flame, it is a sensitive piece of equipment and has failed.