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stack relay switch on an oil fired heaterRepair Stack Relay Switches on Oil Fired Heating Equipment
Service, Test, Repair the Honeywell RA116A RA117A RA817A Control

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Stack relay switch guide for oil fired heating equipment:

Here we explain how to inspect, test, reset, or clean the stack relay switch used as a flame detection/safety device for primary control on oil fired heating systems (boilers and furnaces). Typical protect-o-relays covered are the Honeywell Type RA116A, RA117A, RA817A controls.

This article series answers most questions about central heating system troubleshooting, inspection, diagnosis, and repairs. We describe how to inspect, troubleshoot and repair heating and air conditioning systems to inform home owners, buyers, and home inspectors of common heating system defects.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

- Daniel Friedman, Publisher/Editor/Author - See WHO ARE WE?

How to Service, Testing & Repair the RA116A/ RA117A RA817A Protectorelay Stack Relay Oil Burner Primary Control

Protectorelay scavenger timing and recycling timer (C) Daniel Friedman Audel

Do not lubricate the primary control parts with oil.

Keep the cover on the primary control - this protects the control from dust and from mechanical damage, either of which could make it stop working or make it unsafe.

How to check the safety lockout function

 of the oil burner primary control or stack relay or Protectorelay®:

Pressing the red "reset" button

while the oil burner is running normally will also interrupt or stop the oil burner.

Turning off electrical power to the oil burner,

with the burner running, will of course stop the burner. But loss of power should not trip the stack relay switch. This means that when electrical power is turned back on, provided the thermostat is calling for heat, the oil burner should start.

Check the Scavenger Timing cycle 

of the primary control, using the procedure at SCAVENTER CYCLE RESTART DELAY TIME

-- the above is paraphrased from Audel with some details added from Honeywell's Protectorelay® control installation literature.

How to Test the Stack Relay using the Safety Switch

At CAD CELL RELAY SWITCH we describe using the safety switch, a small black plastic or metallic lever found next to the reset button on some primary heating system controls including stack relays and cad cell sensors.

When to Clean the Oil Burner Stack Relay Switch

Since this oil burner relay switch depends on sensing the heat of the flue gases as they pass through the flue vent connector (or "stack pipe") from the oil burner/combustion chamber in a furnace or boiler up to the chimney, the sensor, a bimetallic spring, is exposed to soot in the oil burner exhaust. If the oil burner has been running poorly, perhaps itself needing cleaning or adjustment, the level of soot in the oil burner exhaust can be quite high.

Soot produced by oil combustion (or by poor or incomplete heating oil combustion) is itself an insulator.

Not only do we need to remove this soot from inside of a furnace or boiler in order to get the most heat from our heating oil into the building's heating distribution system (hot air or hot water), but this same soot can collect on, clog, or insulate the oil burner stack relay switch.

Soot collected on the stack relay switch bimetallic sensor spring, acting as an insulator, can "fool" the switch into thinking that there is not good combustion (temperatures look too low at the sensor) and thus it might switch off on safety and need to be frequently "reset" to keep the heating system running. It may be necessary to clean the stack relay switch sensor.

During oil burner service for a boiler or furnace, if the heating system uses a stack relay switch (which in fact is rather obsolete), the switch should be removed during system cleaning (when you remove the flue vent connector piping), and its external parts or sensor should be cleaned (normally by light brushing).

When & How to Adjust the Oil Burner Scavenger Cycle Restart Delay Time on the RA 116A Protectorelay Switch

Protectorelay scavenger timing and recycling timer (C) Daniel Friedman AudelThe following procedure, recommended by Frank Graham of Audel, tests the scavenger timing cycle of an oil burner that is controlled by a Type RA 116A Protectorelay or "stack relay" primary control.

When an oil burner is in proper adjustment and is working but has been shut off using the electrical power switch (line switch) to the oil burner, the scavenger timing is checked by turning on the oil burner at the line switch.

See ELECTRICAL POWER SWITCH FOR HEAT.

The oil burner should start and operate normally.

As the oil burner runs from the moment you've switched on its electrical power, you should see the clutch outer finger move outward until it engages the stop arm (#2). The drive shaft (#4) should continue to move outwards after the clutch finger reaches the stop arm. Only a small amount of movement is needed, but it's very important.

-- the above is paraphrased from Audel

General Electric, Penn & Honeywell Protecto Relay RA116A RA116A RA817A Manuals & Wiring Diagrams

GE General Electric Master Oil Burner Control GE CR7865 A101B2, CR7865A101 wiring diagram at InspectApedia.com

Above: wiring diagram for a General Electric Master Oil Burner Control GE CR7865 A101B2, CR7865A101.

[Click to enlarge any image]

Below: wiring details for a GE primary control General 5520 Series 10 & Perfex 5500-5520 in a "re-manufactured" GE stack relay provided by Sid Harvey.

wiring details for a GE primary control General 5520 Series 10 & Perfex 5500-5520 in a "re-manufactured" GE stack relay provided by Sid Harvey. (C) InspectApedia.com

Below, wiring for a Honeywell stack relay.

This wiring diagram for a typical Honeywell Intermittent Stack Relay was pasted on the interior of a replacement unit from Sid Harvey, courtesy of reader Deb 2020/02/03.

Honeywell or Sid Harvey Oil burner stack relay wiring diagram - Sid Harvey at InspectApedia.com reader Deb

For replacing a bad RA116A RA117A or RA817A see the following:

Penn Oil Burner Primary Control Stack Relay (C) D Friedman Ben Bourdreau

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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2017-01-29 by Sean

I have an old oil fired boiler with a Honeywell Type RA117A... Getting power to the ignitor but no power to the burner motor... Guessing I have to replace the stack relay unit... As a temporary fix, can I attach the burner motor wire to the ignitor contact? Thanks for any advice...

On 2016-11-08 - by (mod) -

According to Sid Harvey, the R20R is a remanufactured control intended to replace the original RA116A stack relay.
http://orders.sidharvey.com/

I think the Honeywell RA116A-R20-R is simply a designation that you've found a re-built RA116A control - that ough to work. I give contact info for Honeywell - you can also call them to double check.

At https://customer.honeywell.com there are 65 versions of RA116 relays listed; the company says the RA116A23 series is obsolete and no longer available. In fact per the manufacturer, most of the older RA116's are considered obsolete. Current models listed by Honeywell include RA116A1055/U and RA116A1063/U.

At Sid Harvey you will also find older relays, including the Honeywell RA116A-R20R sometimes "new old stock" or re-manufactured controls that would most-likely be safer than a used control or a control of unknown condition listed on e-Bay (for example).

If changing the stack relay you need to match the probe's insertion length as that's a key variable among the various models - you want a probe that inserts the same as the original manfacturer's unit that you're replacing. Inserting a probe that is too short, too long, or that touches another metal or part in the heater would prevent proper operation leaving the system unsafe.

Another variation may be the number of seconds before the control trips off on safety - typically about 75 seconds.
Other control variations to watch for:
120 vs 240V
Constant vs. intermittent ignition burner. The RA116A stack relay is used with "intermittent ignition" oil burners, previously called "constant ignition" oil burners.

I'm nervous about installing a used control of unknown condition on a heating system, particularly when it's a safety device as is this protect-o-relay. A bent or damaged bimetallic spring, a damaged internal relay or spring, even a corroded contact could make the system unsafe, risking fire or worse.

If you don't have the Honeywell RA116A-RA117A-RA817A product guide contact me by email using the page top or bottom CONTACT link and I'll send you a copy of that PDF

On 2016-11-06 by JRyck

I have a RA116A23K-10 on my heater right now and it is acting up. I have found a RA116A-R20-R for sale. Can I change it out with it.

On 2016-10-09 - by (mod) -

Watch out: I would replace the part. DO NOT try lubricating it as even if that works in the short run it's likely to damage the control and may jam it. Such may be unsafe.

Continuing:

If the burner is turning off the Stack Relay could be causing that IF in fact the burner flame is very poor, weak, sooty, OR if the control itself has become sooted and dirty, as it may then fail to properly sense stack temperature. If that's happening I'd expect the relay to shut down the burner in about 30 seconds or less.

Other causes of shutdown could be in the fan limit control.

On 2015-11-24 by Erik

On my RA116A, the system (oil burner, fan, etc.) is sometime not coming on immediately after the thermostat calls for heat. After opening the panel, I notice in the upper left hand corner what appears to be a solenoidal switch. If I jostle it a bit, the system pops on and all works normally until at some point in the future when it needs to be done again.

Can I lubricate this part?

On 2015-11-03 - by (mod) -

Darek,

Watch out: Use the on-page search box at the top or bottom of this page to search inspectapedia.Com for OIL BURNER PUFFBACK explosion and you'll see where the system is heading. It needs proper cleaning and adjustment. Discuss the concern with your heating company service manager

On 2015-11-03 by Darek

My furnace makes boom noice on star time once a time and smoke comes out .Just been clean by professional company


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Continue reading at STACK RELAY REPLACEMENT CROSS REFERENCE CHART for a guide to replacements for the RA116A RA117A RA817A controls or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

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