Boiler Riello RDB - hums & clicks but won't start

Stove25 · 20-11-2024 10:08PM #1

Hello, looking for advice with an Oil boiler - Riello RDB 2 burner. It hums for about 10 secs then theres a click of the solenoid and then a louder hum for a short while and then it locks out. Can sometimes get it started by tapping the pump or wiggling the whole burner. When it does go, it could keep going for an hour or more but will eventually lock out - assume when trying to restart having cut out after getting to boiler thermostat temp.

I guess options are motor, pump, solenoid or capacitor ?

Lenar3556 · 20-11-2024 11:53PM

When you say humming, is the motor/fan actually starting?

The motors themselves don’t give much trouble.

If the issue is a stalled motor and rocking / tapping overcomes the issue, my first stop would be capacitor, followed by pump.

Stove25 · 22-11-2024 01:26AM

No, the fan doesn't kick in. When the burner does start after giving it a tap, the fan starts and then after 5 secs or so, it ignites and away it goes.

If it's the capacitor and there isn't enough charge in it, how would giving it a tap help to get it going ?

Lenar3556 · 22-11-2024 11:58AM

The capacitor is for starting the motor. If it was faulty or weak, the motor will still start if it gets some help.

But a stiff oil pump, or worn motor bearings could cause similar symptoms.

John.G · 22-11-2024 04:00PM

https://www.boards.ie/discussion/comment/122868394#Comment_122868394

The fan & oil pump are driven from the same motor, I would try a capacitor first.

Stove25 · 23-11-2024 02:25PM

Have installed new capacitor. Fan now kicks in straight away and burner ignites 😀

Don't see any polarity on the new or old capacitor. For other capacitors it can matter which way around they are connected but for these burner ones ? Its a TEKNO 45 same as one that it replaced.

Lenar3556 · 23-11-2024 08:15PM

that’s great.
polarity doesn’t matter for those capacitors

Boiler Riello RDB - hums & clicks but won't start

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