Riello F5 Fast, Fluctuating Pump Pressure

gschabel

Greeting all.

Have a Riello F5 for a while, love it. Back when it was on a single line system, I could check/dial in the pump pressure and the gauge read and responded to what I would set without much gauge fluctuation. The gauge remained steady at whatever pressure, both pre and post purge.

We have changed to a 2 line system with our new oil tank, and when I check the pump pressure, the gauge fluctuates quickly (actually looks like fast fluttering) within a 20psi range. I can adjust the pressure, but it is not as responsive as I recall with the single line system, and as I turn it up, it does revert back (lower) a bit with each increase, and seems not to want to go higher than 160psi. (I didn't want to push it either)

Question: Is this normal for a 2 line system with Riello or is the pump malfunctioning?

This is not a Tigerloop, just a return to the tank. The burner is working without issues.

Thanks in advance for any insight on this.

SuperTech

Definitely not normal. Why did you switch to a two pipe system? A single pipe, gravity fed setup is the best way to go. Why are you adjusting the pump pressure so much? It should have been the same regardless of wether it's a single pipe or two pipe. Are you confirming that the combustion is set for a true zero smoke with a digital combustion analyzer each time you change the pump pressure?

The pump pressure should be set for the manufacturer specification when the burner is installed and it should never be messed with again. What is the manufacturer specification for pump pressure? It sounds like you probably have some leaks on the suction line and getting air in the lines. Or possibly the pump is screwed up from you playing with it so much.

Big Ed_4

Do you have a Riello pressure gauge still connected to the burner ?

gschabel

The gravity feed tank rusted out and a Roth top fed tank was installed. The self prime feature of the 2 line system is favorable. I don't check the pressure often nor adjust it, last time was probably about 5 years ago with the old tank and single line system. I usually just check and no adjustment needed. As I do my own maintenance, I decided to check and found it fluttering around. Pressure had been at 165 with the single line system which is spec.. The burner is running at 0 smoke. I will check the suction lines for air leaks and insure that they are tight. I have a dual filter system and they were all filled to the top with oil when I serviced them and did not see any air pockets. Thanks for the feedback! I have the Riello kit, so if the pump craps out, I have a spare ready to go!!

EdTheHeaterMan

The only thing I can think of that can cause the fluttering you are talking about is air in the high pressure fuel section of the pump/line on the Riello.  Air can be constantly added to the pump gear set if there is a bad flare on one of the connections to the top of the tank.  That would be an air leak in, not a fuel leak out of the fuel line.   If you were to pressurize the fuel line with about 2 to 3 PSI of air pressure and look at the leaking fitting, you may see fuel coming out of the leaking flare.  If you don't see any fuel coming out, then you can spray soap bubbles on the fittings and see if there are any bubbles forming on the fittings. Just like using soap bubbles on refrigerant lines to check for leaks. 

Big Ed_4

If the pressure fluctuates below the set point of the pump you have a suction problem , if the pressure fluctuates higher then set point , you have a return line issue ….

HVACNUT

You'll be able to see the bubbles and why pressure fluctuates. Hold a flashlight under the clear tubing, play "Sunshine Superman", and watch the psychedelics.