Gas/Propane Basics
Timmie McElwain
President, Gas Appliance Service
timmcelwain@gastcri.com
Introduction to Modules Used
on Intermittent Pilot Systems:
Part 1
Our emphasis will be on forced
hot water and forced warm air
systems used on both natural
gas and propane systems.
There are many differences between gas and oil
hydronics. The obvious one is that the burners
and fuels are different. The controls, however,
are typically the same—with some exceptions. In this
new series of articles, I am going to address some
of the differences and how to work with them. Our
emphasis will be on forced hot water and forced warm
air systems used on both natural gas and propane
systems.
We will be emphasizing the older systems and not
explore any modulating/condensing equipment. I want
to address controls that are unique to gas. As we look
into some more modern systems and what specific
problems they present, it is important to understand
the basic fundamentals associated with these systems.
Most of our modern heating equipment, in some way
or another, involves electronics and with the electronics
the use of flame rectification as a safety and flame
proving system. It does not matter if it is a forced
warm air furnace or a forced hot water boiler, the same
basic system is used to perform safe ignition and then
consistent operation throughout the entire call for
heat.
There are, however, different ways it is applied from
intermittent pilot application to direct spark ignition
and including hot surface ignition. Each has its own
distinct advantages and problems. In this next series,
we will provide corrections and diagnostics to help
solve those problems.
We will start with the basics and go from there into
operation, typical problems, diagnosis, troubleshooting
procedures and hopefully a final solution to your
particular problem. It is easy to jump to conclusions
with these systems and just change parts until you
hopefully solve the problem. That is, however, timeconsuming
and costly.
A Universal Replacement for IP Ignition Modules
The Honeywell S8610U Electronic Control Module control
system has gone through several revisions. In this
article, we will cover the original, which is identified by
its gray plastic case.
The S8610U Universal replacement module was developed
as a replacement module in the early 1990s for
single and dual rod intermittent pilot systems. A new
version has been added, which is the S8610U-3009;
it has some added features that the original S8610U
did not have. The older version will first be addressed
and then we will go over the new version in the next
article.
Intro/Advantages of Universal Replacements
The Honeywell S8610U Electronic Control Module
was developed as a universal replacement module for
single and dual rod intermittent pilot systems. We will
explain how to decide if the module is an appropriate
replacement for a particular application, and describe
in later articles the Y8610U Retrofit Kit.
Universal replacements provide dealers and service
technicians with important advantages—they reduce
the inventory that must be carried on the service
vehicle and stocked at the shop and they minimize the
number of controls the service technician must master.
Working with familiar controls on a routine basis allows
the service technician to develop greater confidence
in his or her ability to safely install, test and
troubleshoot the system. This results in faster, easier
installations with fewer callbacks.
Features of the S8610U
The S8610U is
a 24V electronic
module for intermittent
pilot
systems. It has
100% shutoff with
continuous retry
and can be used
with both natural
gas and LP.
18 ICM/July/August 2019