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Wiring a gas oven

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Does anyone have experience with wiring a professional gas convection oven? I purchased an old unit which was in a bad condition and of which rodents ate most of the wiring. There also seemed to be some previous repairs made with newly added components. I already fixed all the mechanical and structural bits and the unit looks as good as new now. I think I figured out which electrical components were original and apart from the gas solenoids and motor I purchased all new components from China, so I’m sure all works again as intended. So now I’m stuck with a box of components, not knowing how to connect what. I reached out to the manufacturer regarding a wiring diagram but they won’t help me, only sell me a new oven. Specifically the magnetic contractor, thermal relay and timers have too many connection points for me to understand. HELP!!

 

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Do you have a photo of the actual oven and the components?

A name and type would help too.

 

The basic wiring is same with microwave and other ovens.

This one is just extra with valves and electronic thermostat, and double.

And we need to know what power you are supplying , 230 or 400 volt.

(only give away is the 230 volt at the igniters, but even those can be pulled down from 400)

 

Capacitor goes to the motor. You drawed 4 wires and ground, without knowing the type I only could guess that the other wires is for pulling down the voltage.

Red Green wire from the probe go to pin 4 and 5.

6 and 7 or 8 is for the power input, and 1 and 2 is relay switch for the thermo relay for the motor and to the igniter for high low setting.

 

It is complex to explain without visual information.

 

A two floors pizza oven? 🙂

 

 

Edited by Metropolitian

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Hi Metropolitan. Thank you for trying to explain, but as you say without a visual it gets complicated. Did you see the schematic drawing in my original post? It has all the components and type numbers in there. Along with some of the connections which are clear and easy. 

The oven is a Chinese Flamemax HGA-5 220V. 

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WARNING - Gas oven controls should only be serviced or re-worked by a competent person who understands the automatic ignition system and safety features.


You need to know the operation procedure of the oven and it two gas valve sets and blowers to properly determine how the controls should be wired. I guess there are two levels of bake in a single zone.

Some ovens have one blower fan shared by all gas valves via a relay, others have separate blowers for each gas valve zone wired directly to the igniters.

 

I recognise the igniter types from a Ying Ding brand X bread oven we repaired a while back which only had one set of gas valves.

It operated as follows :-

 

A bake timer and 'on' button powered the process.

The igniter received power (220v) from the temperature controller when heat required.

Igniter starts blower fan via a contactor, opens pilot gas valve (24v), sends high voltage to the ignition electrodes and then uses flame rectification to detect flame present via the ignition electrode ground wire. Main gas valve opens (24v) when flame detected. Indicators will show flame fail or flame good.

A separate timer operated the water misting valve directly via separate on/off switch.

Edited by Fruit Trader
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With no help from the manufacturer this will be fun, not.

 

Did you take any photos before stripping out the old wiring, even if the rats had got much of it there would still be clues.

 

Best bet would be to find someone with the same unit and take some photos of the panel wiring.

 

If you have a local place selling / repairing that brand they may be able to fix it.

 

 

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For others who wish to play along ..

 

Chinese 5 tray gas Convection oven

 

oven.jpg.cc7431332aa359da9ac70eb22060b583.jpg

 

 

Edited by Fruit Trader
  • Like 2

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30 minutes ago, Fruit Trader said:

WARNING - Gas oven controls should only be serviced or re-worked by a competent person who understands the automatic ignition system and safety features.


You need to know the operation procedure of the oven and it two gas valve sets and blowers to properly determine how the controls should be wired. I guess there are two levels of bake in a single zone.

Some ovens have one blower fan shared by all gas valves via a relay, others have separate blowers for each gas valve zone wired directly to the igniters.

 

I recognise the igniter types from a Ying Ding brand X bread oven we repaired a while back which only had one set of gas valves.

It operated as follows :-

 

A bake timer and 'on' button powered the process.

The igniter received power (220v) from the temperature controller when heat required.

Igniter starts blower fan via a contactor, opens pilot gas valve (24v), sends high voltage to the ignition electrodes and then uses flame rectification to detect flame present via the ignition electrode ground wire. Main gas valve opens (24v) when flame detected. Indicators will show flame fail or flame good.

A separate timer operated the water misting valve directly via separate on/off switch.

The process you describe seems the same for my oven, except that it has two igniters. I understand how the gas is controlled and ignited using the igniter units. The operations I’m not fully sure about are:

 

- are the two igniter working in parallel so either both on or off, or is it supposed to be two on for quick heating and only one to keep the temperature stable? And in the latter case, how is my thermostat supposed to control that?

 

- Is the blower supposed to run continuously or only when gas is being burned? I assume it runs all the time, otherwise when inserting the water at a moment the oven is hot enough and it’s not burning, it won’t be spread around and turn into steam quickly. So that means it’s connected directly to the bake on/off switch / timer? And in that case what are the remaining two orange colored wires for coming out of each igniter? I found sone schematics online for the igniter, but the only one in English labeled them as ‘fan’. Is it to connect a cooling fan to them? The original units were partly melted, so that would make sense.

 

- why are there 2 sets of wires coming from the blower motor? There is no writing anywhere on the motor so it’s a complete guess what type of motor it is. 

 

- for the spray function there is a timer (up to 99 minutes) in the front panel, but a separate timer (up to 3 seconds) inside the machine. I understand the internal timer is just to set to the duration the spray lasts, and doesn’t need regular change. So the timer on the front panel is set to count down to the moment the internal timer should go on?

 

- There is a door sensor installed. When the door opens with the unit on, what parts should turn off? Just the blower motor or also the igniters or just turn off everything? And in the last case that means I assume the timers are placed before the door sensor, so they remember their countdown?

 

fun project so far!!

 

i received most components already, just waiting on some new switches and the water solenoid. 

 

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56 minutes ago, Crossy said:

With no help from the manufacturer this will be fun, not.

 

Did you take any photos before stripping out the old wiring, even if the rats had got much of it there would still be clues.

 

Best bet would be to find someone with the same unit and take some photos of the panel wiring.

 

If you have a local place selling / repairing that brand they may be able to fix it.

 

 

Yeah, I’ll have a drive around the pro kitchen suppliers, to see if they have a similar oven for sale, which I can peek inside. It’s a fairly common model, just rebranded to sold locally. 

I made a photo of how it looked before, but it really was a mess with I think a replaced basic thermostat added inside (I guess the original panel mounted one was broken). Most components were partly melted also, after a previous rodent attack. Of course when it was fixed then the repairman just added some parts and wires and left all the old bits and pieces and just wiring it up so the basic functions worked again. 

1C6FD652-F0DC-47CF-9A88-E3E547A24BAA.jpeg

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I see what you mean about Roland Rat having a go.

 

If you can find a friendly place they may even let you sight a service manual (use your phone on the diagrams).

 

A little "lubrication" in the service department can work wonders :whistling:

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Just now, Crossy said:

I see what you mean about Roland Rat having a go.

 

If you can find a friendly place they may even let you sight a service manual (use your phone on the diagrams).

 

A little "lubrication" in the service department can work wonders :whistling:

The lubrication is a good idea. I heard there is a technician from a large hotel/bakery supplier who does repairs on the side. If all else fails I’ll get his details. But I’d like to fully understand how it works so I can do future repairs myself. It doesn’t look like rocket science, I just have no experience with wiring timers and relays.

  • Like 1

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I don't have much time to study the photo at the moment but I can see the igniter blower cables were originally cut and redundant which leads me to believe the blower was switched on with the main cook timer and went off along with the burners when the door was opened. Blower induction motor was controlled via contactor and start/run capacitor.

 

PS

The oven thermostat with capillary tube ??

Edited by Fruit Trader

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2 hours ago, Fruit Trader said:

I don't have much time to study the photo at the moment but I can see the igniter blower cables were originally cut and redundant which leads me to believe the blower was switched on with the main cook timer and went off along with the burners when the door was opened. Blower induction motor was controlled via contactor and start/run capacitor.

 

PS

The oven thermostat with capillary tube ??

Thank you. 

I found a 50 Baht thermostat inside with a capillary tube. But I think some repairman added that later as a cheap fix. Originally it has a ‘smart’ thermostat with a thermocouple probe, so I ordered those as replacement to make it original again. 

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