Riello G5X Oil Pump By pass screw

John.G

I just came across the by pass screw for the above which isn,t fitted as my Oil Tank is above the pump suction, I understand that this is only fitted when there is a return line installed as in a Tiger Loop system.

Single Pipe System
With no by pass screw installed does the "leak off" from the pump pressure adjusting screw return to the suction side of the pump?......if the by pass screw was then installed would the pump pressure be uncontrollably (high) as the leak off from the pump pressure adjustment would have no where to go??

Two Pipe (Tiger Loop System)
With the by pass screw installed (as it should) does this mean that the leak off from the pump adjustment screw is prevented (blanked off) from returning to the pump suction but is returned (diverted) instead to the second pipe and thence to the Tank.
What is the effect if the by pass screw is not installed, could one still get the desired Pump Pressure by using the adjustment screw?

jimf

with the by pass screw fitted to a single pipe installation the pressure goes through the roof and pops the weakest point usually the pump seal


ive seen it happen only a couple of weeks ago on a brand new install



the screw comes with the boiler not fitted in the pump for this very reason and knowingly has to be fitted

years ago it was the other way around and had to be removed from the burner pump

John.G

jimf wrote: »

with the by pass screw fitted to a single pipe installation the pressure goes through the roof and pops the weakest point usually the pump seal


ive seen it happen only a couple of weeks ago on a brand new install



the screw comes with the boiler not fitted in the pump for this very reason and knowingly has to be fitted

years ago it was the other way around and had to be removed from the burner pump

Thanks,
It took me a while to realize that the bypass screw is actually a blanking screw so I can see quite clearly now why the pump/seal would be wrecked, I can,t remember if it came un installed in my 2005 Firebird but I think it did.

jimf

the old way was a tee with the 2 hoses connected and the by pass screw fitted

im not sure why it was done this way something to do with cooler operation I think


the real old fella on here WEARB will probably be on later when he wakes up from his nap and will surely explain better


he used to service the boiler on the titanic I believe

John.G

All 29 of them!!, so he must know a lot about solid fuel (coal) boilers as well.

Wearb

Just seeing this now. Well you can all faf off. I’m going to watch the rugby and then a ðŸº

jimf

Wearb wrote: »

Just seeing this now. Well you can all faf off. I’m going to watch the rugby and then a ðŸº

well im sure the rugby will be better than watching yere hurlers :pac::pac::pac:

Wearb

jimf wrote: »

well im sure the rugby will be better than watching yere hurlers :pac::pac::pac:

Waiting 43 years to crow 👅

jimf

Wearb wrote: »

Waiting 43 years to crow ��

and by jaysus crow we will

Wearb

jimf wrote: »

and by jaysus crow we will

Fair play to you. I was tempted to go down for the craic. I have friends in Adare

jimf

adare is only about 15 mins drive from my tent

agusta

John.G wrote: »

Thanks,
It took me a while to realize that the bypass screw is actually a blanking screw so I can see quite clearly now why the pump/seal would be wrecked, I can,t remember if it came un installed in my 2005 Firebird but I think it did.

The pressure in the pump would go to 20 bar plus.

John.G

agusta wrote: »

The pressure in the pump would go to 20 bar plus.

I suppose theoretically the sky's the limit, it would depend on the pump gear clearances to allow leakage back to the suction side, one might possibly get away with it on a pump with thousands of running hours and a lot of wear, have you come across this yourself where it didn,t blow the seal or whatever?

I think I read somewhere (on here?) where some one was looking at getting a turn down of 50% with a single stage oil pump by regulating the oil pressure somewhere between 8 bar and 30 bar, there are oil boilers out there with two stage systems I think that give a form of modulation.

Anyway I came across the attached Danfoss info that I think is excellent.

agusta

John.G wrote: »

I suppose theoretically the sky's the limit, it would depend on the pump gear clearances to allow leakage back to the suction side, one might possibly get away with it on a pump with thousands of running hours and a lot of wear, have you come across this yourself where it didn,t blow the seal or whatever?

I think I read somewhere (on here?) where some one was looking at getting a turn down of 50% with a single stage oil pump by regulating the oil pressure somewhere between 8 bar and 30 bar, there are oil boilers out there with two stage systems I think that give a form of modulation.

Anyway I came across the attached Danfoss info that I think is excellent.

I was changing a 15 year old riello burner from a two pipe to a one pipe, removed the bypass screw, Fitted pressure gauge and pressure went up to the end of the pressure gauge,20 bar plus, Damaged my pressure gauge. My thinking was the port in front of the bypass screw was blocked,so even though i removed the bypass screw, the pump worked as if the by pass screw was still fitted.

John.G

agusta wrote: »

I was changing a 15 year old riello burner from a two pipe to a one pipe, removed the bypass screw, Fitted pressure gauge and pressure went up to the end of the pressure gauge,20 bar plus, Damaged my pressure gauge. My thinking was the port in front of the bypass screw was blocked,so even though i removed the bypass screw, the pump worked as if the by pass screw was still fitted.

Were you able to get the pressure back to normal and did you re use the original pump?. If the nozzle was actually operating at 20 bar plus, then burner must have been overfiring by over 40 p.cent accompanied by a touch of black smoke

jimf

John.G wrote: »

Were you able to get the pressure back to normal and did you re use the original pump?. If the nozzle was actually operating at 20 bar plus, then burner must have been overfiring by over 40 p.cent accompanied by a touch of black smoke

didn't I tell you those aldi pressure gauges weren't up to scratch :p:p:p

agusta

The pump would not adjust back. once the burner started and i saw the 20 bar i switched burner off.i certainly knew something was wrong with loud sound/vibrations through the flue. I refitted the bypass screw and fitted two new riello hoses.The only reason i was converting to a one pipe system was to fit only one riello hose

agusta

jimf wrote: »

didn't I tell you those aldi pressure gauges weren't up to scratch :p:p:p

mm,Did you wake up

jimf

agusta wrote: »

mm,Did you wake up

just about up hard session last night

had 2 packets of wine gums

agusta

i heard your not allowed out:)

jimf

agusta wrote: »

i heard your not allowed out:)

see I am allowed out and home even later than you