Are RTCU700609 and RTBF800164 the same thermostat?

This page answers one question for buyers, maintenance technicians and parts distributors: can RTCU700609 be used in place of RTBF800164 in a commercial fryer? It is a part-number comparison, not a sales page — nothing here is offered for sale and no price is quoted.

Source basis: Hobart parts diagrams and distributor listings.. See Sources, method and reliability for what is verified and what is not.

Short answer: No. RTCU700609 is the electronic regulating thermostat (105-185 C) for Hobart HEF-series fryers. RTBF800164 is the separate high-limit thermostat. They do different jobs and are not substitutes for each other.

At a glance

	RTCU700609	RTBF800164
Function	Regulating thermostat	High-limit thermostat
Range	105-185 C	High limit (fixed)
Role	Controls oil temperature	Cuts out on over-temperature
Interchangeable	No	No

What to check before swapping

Identify which device failed before ordering. A regulating fault and a hi-limit trip look similar from the outside.
Confirm the model - HEF47, HEF77 and the BCE/BMЕ variants use different builds.

When you should not swap

Do not replace a hi-limit with a regulating thermostat.
Do not assume two numbers on the same parts diagram are alternatives.

Documented wording

These are the lines that decide the answer above, quoted as published. A paraphrase would hide the unit labels and the quantity column, which is where most of the confusion comes from.

Document	Wording (verbatim)	What it settles	Link
Cater Spares UK listing for RTBF800164 (distributor wording, not OEM)	“HOBART RTBF800164 ELECTRIC CHIPS FRYER SAFETY HIGH LIMIT CUT OFF THERMOSTAT 225c”	The RTBF side is documented as a safety high-limit with a 225 C cut-out. Note that other UK listings quote 232 C for the same number — check the marking on the part you remove.	Cater Spares UK

Sources

Hobart parts diagrams and distributor listings. Verify against your own equipment's parts manual before ordering. This is not an offer or a quotation.