More information on How Intermittent pilot Systems began (5059 Control Discussion)

Tim McElwain

A few days ago in the controls section here on the wall a discussion developed concerning a White Rodgers 5059 Relite Control. I mentioned that this was one of many systems from the Late 1970's and early 1980's that were developed to replacing standing pilot systems. This was a time when some of the control systems developed by manufacturers were perhaps pushed into the market place to quickly. There were many problems with those early systems. I would like to address some of those and at the same time help everyone to know how to deal with some of these systems which are still around. I will take this slowly and try to answer any questions which may arise.

ratio

We're all ears, @Tim McElwain!

Tim McElwain

In the late 70's early 1980's things on the gas side of the heating business began to change.

The first thing all manufacturers of gas equipment looked at was getting rid of standing pilots on gas heating equipment. This was probably due to some pressure from the government along with the potential for eventually running out of gas (this was before fracking).

Most of the companies that produced gas controls did not have any flame rectification systems on residential equipment. it was only on commercial equipment. The big companies White Rodgers, Robertshaw and Honeywell were all scrambling for putting out a system which eliminated the standing pilot. The only company that had an existing system at that time was Johnson Controls. They also were the only company with the module and gas valve combined in one control. The module was mounted on top of the gas valve, it could also be a separate cabinet mounted module and separate gas valve. They were way ahead of their time. That first Johnson controls was the G33 control it used a spark to light a pilot but proved the flame with a thermocouple attached to the G33 Module.

The G60 series replaced the G33 and then eventually today the G600 which used a high voltage spark to light the pilot and proved the flame using flame rectification with microamps. This G600 control was unique to the residential gas side. None of the other manufacturers had an intermittent pilot system for residential use. This meant the scramble was on to be first with a system. I will address the White Rodgers 5059 control first as it was the system that was covered in the controls section.

Tim McElwain

The White Rodgers System

Tim McElwain

Better Picture

Tim McElwain

The White Rodgers Cycle Pilot used a White Rodgers 36C80 Gas Valve it was a redundant gas valve (dual seated) which means it met the 1979 code requirements for valves used on gas heating. It was used in conjunction with a 3094 Plug in Pilot which was a single pole double throw mercury pilot switch and flame sensing element. Used to prove the pilot flame. In the hot position, the switching action provides electrical power to open the main burner valve. Early versions of this system had problems with the pressure switch in the gas valve. This was the beginning of problems with this system. The solution was the Electrical-Quick-Shutoff (EQSO) resistor which was placed on the plug in and then became a part of the ignition system. The resistor is wired in series with the redundant valve in such a manner as to force the system to recycle in the event of a momentary power interruption. If it was recycled rapidly it was known to cause delayed ignitions.

Tim McElwain

Sensor Plug and Socket

Tim McElwain

Wiring

Tim McElwain

Internal Gas Flow

ch4man

oh about a month ago I repaired an old Trane with the EQSO system. i was shocked to find a replacement valve as I thought they weren't available.
if the valve didnt do the trick I was ready to modernize to flame rectification

Tim McElwain

At one time Weil McLain was offering a HSI Kit to replace the White Rodgers system. I am not sure if that is still available.

Tim McElwain

Troubleshooting:

More on next page:

Tim McElwain

Tim McElwain

Tim McElwain

Unless there are some questions this wraps up the discussion on the White Rodgers 5059 system. There were also problems with Robertshaws and Honeywells first attempts at Intermittent pilot on the residential side. I will cover those in a separate posting.

Tim McElwain

Did this help anyone to understand this old system?

mattmia2

i need to stare at the schematic a bit more and think about what the resistor is doing.

Steamhead

Tim McElwain said:

Did this help anyone to understand this old system?

It brought back memories of when I came to your training center. I use that knowledge every day I work.

ch4man

mattmia2 said:

i need to stare at the schematic a bit more and think about what the resistor is doing.

it takes less voltage to hold open a valve coil than open it. the resister dose just that when switching from the cold contact to the hot contact the reduced voltage is still enough to hold open the pilot valve while its switching to the hot contact. it also keeps the pilot valve from opening until it can safely do so.

or something of the sorts

Solid_Fuel_Man

So the Johnson Controls was fairly problem free from the beginning with a thermocouple for pilot detection?

Tim McElwain

The Johnson Controls system has been pretty much trouble free since its beginning. It is still available today through Baso Gas Products LLC. The system before Johnson sold out to Baso Gas products was the G600 series. That is now replaced by the Baso BGQ15HAA-1 retrofit Gas Control System.

The system originally was the G33 series with the thermocouple to prove the flame. It then transitioned to the G60 Flame Rectification system and finally the G600 Series before Johnson sold its gas division to Baso Gas Controls LLC. These systems have been pretty much trouble free.

Tim McElwain

The EQSO resistor was incorporated into the system to resolve pressure switch problems. mattmia2 covered it pretty well in his explanation.