I 'googled' and found pieces parts of answers to this problem, but
nothing conclusive, so I'll start anew:
We have a Cozy Counterflow wall furnace Model CF558B. Bought and
installed in 1996. Originally propane, converted professionally to
Nat. Gas. in 1998. Unit has a RobertShaw SP735A ignition control.
Problem: the furnace takes about 15-20 seconds, occasionally up to 45
seconds to ignite when turned on. The pilot lights immediately, but
the furnace keeps sparking and sparking (that's the source of the
tic-tic-tic). Sensor does stick up well into the pilot flame. When
furnace finally does light, it operates normally.
Attempted Fix 1: Had the local furnace company who did the conversion
come back and adjust the furnace. After paying over $200 for the
service call, the problem returned after a few months.
Attempted fix 2: I bought and installed a replacement sensor, trying
the easy fix first. No change.
So, I guess the next option is to replace the RobertShaw SP735A
ignition control. From what I've found and read:
- many feel the RobertShaw ignition modules are poor quality and
recommend replacing with a Honeywell Universal module.
- there was mention of a recall of RobertShaw equipment, but I could
only find information about old 1984 recalls of LP valves and a new
recall of scuba equipment.
So my questions:
1) Does this sound like an ignition control problem? Are the
Honeywell universal ignition modules really worth the $50+ more than
just purchasing a replacement RobertShaw?
2) The parts list for the furnace list different pilot assemblies for
Nat. Gas and LP. I don't recall the pilot assembly being changed when
the unit was converted to Natural Gas. Are the pilot assemblies so
radically different for each gas that this could be causing the
3) The parts list also lists two different ignition modules for each
gas. Does anyone know if the RobertShaw SP735A is the Nat. gas or the
LP ignition module? (I also have a email into Louisville Tin asking
4) Has anyone heard if there is a recall of RobertShaw ignition
controls, specifically the SP735A? Details?
Estes Park, Colorado