Overview
Thermal valve retrofit kit for Sapphire Scientific truckmounts. Sapphire part number 48-168. It replaces the original 165 degree thermal relief valve (23-033).
Why a retrofit kit exists
A thermal relief valve protects the solution pump. When the machine runs with the trigger closed, the pump is working against itself and heating the water it is holding. The thermal valve opens at its set temperature and dumps that heat before the pump seals are damaged.
Sapphire issuing a retrofit kit for a specific valve is a signal worth reading. If you are replacing a 165 degree thermal relief valve on a Sapphire machine, this kit is the current answer — not another original valve.
When to fit it
Fit it if the original valve has failed, and consider fitting it as planned maintenance if it has not been changed.
The reason is the failure mode. A thermal valve that fails closed gives no warning at all: everything appears normal until the pump seals go. A valve that fails open weeps constantly and at least tells you. Because the expensive failure is the silent one, this is a part worth changing on time rather than on symptom.
Fitting advice
Depressurise the solution circuit before you start.
Photograph the original installation — orientation, fittings and where the discharge goes — before you remove anything.
Make sure the relief discharge is routed somewhere safe. A thermal valve that opens is dumping hot water, and where that goes matters in a van.
While the circuit is open, check the by-pass valve and the inline strainer. If the machine has been running hot enough to exercise the thermal valve regularly, those have been working hard too.
Operating advice
The habit that saves pumps is not running a machine against a closed trigger for long periods. The thermal valve is a backstop; every time it opens, the pump has already done work it did not need to do.
Frequently asked questions
Which machines does it suit?
Sapphire truckmounted machines fitted with the original 165 degree thermal relief valve. Send us your model and serial number and we will confirm.
What is in the kit?
Sapphire do not itemise the contents in the documentation we hold, and we are not going to list contents we cannot verify. Ask us before ordering if you need to know.
Can I just fit another 23-033?
You can, but the retrofit kit is what Sapphire now supply for this position. Ask us before choosing the original.
Is this a job for a technician?
It is high-pressure plumbing on a machine that heats water. Competent workshop work rather than roadside work.
Send us your machine model and serial number and we will confirm this is the right kit before you order.
