Horne Engineering Ltd
Issue 7, November 2018
7
If the TSV1-3 fails the thermal shut of test then remove the temperature control knob and the thermostatic
cover (see Installation section for details) and check the internal surfaces for scaling. If the TSV1-3 body
requires descaling then it should be removed from the casing to do this. All rubber parts must be removed
prior to descaling. Do not forget the Slide Valve Seal located inside the TSV1-3 body, which should
always be replaced with a new seal after removal. Maintenance kits are available whic
h contain “O” rings
and/or the Thermostatic Element. Smear al
l “O” rings with silicon oil prior to installing them. Torque the
TSV1-3 cover to 40 Nm (54 lbft). This is to prevent the user from inadvertently unscrewing the cover
during temperature adjustment. Do not over tighten the cover.
Replace the “O” rings every three years (Maintenance kit with spare “O” rings available). Smear silicon oil
on all “O” rings prior to installation. Lightly smear the outside diameter of the slide valve with silicon oil
prior to installation.
Replace the Thermostat Element and slide valve assembly at least once every 6 years in all TSV1-3
valves, or more often if problems are experienced or in installations where the water is aggressive.
The On/O
ff mechanism uses a ½” washer, which should be replaced when it leaks. Remove the cosmetic
trim and unscrew the on/off assembly. The washer is retained by a small nut. Do not over tighten this nut
(torque to 2.5 Nm). Ensure the on/off assembly is torqued down to 25 Nm (34 lbft) to prevent the user
from inadvertently unscrewing the assembly during flow control. Do not over tighten the assembly.
The Check Valves prevent crossflow between hot and cold water supplies under unequal pressure
conditions, and are designed for long life with no maintenance. Their function can be tested as follows:
To test the Check Valve on the hot side, shut off the hot supply and ensure the cold supply is open. Be
prepared for leakage of trapped water from the pipe and remove the strainer basket on the hot side. Any
continuing leakage evident from the strainer body is likely to be coming through the hot supply Check
Valve (N.B. Ensure the hot isolating valve shuts off tightly, or it may cause leakage here).
To test the Check Valve on the cold side, shut off the cold supply and ensure the hot supply is open. Be
prepared for leakage of trapped water from the pipe and remove the strainer basket on the cold side. Any
continuing leakage evident from the strainer body is likely to be coming through the cold supply Check
Valve (N.B. Ensure the cold isolating valve shuts off tight, or it may cause leakage here).
If either Check Valve is leaking then the inlet elbow (complete with Check Valve and strainer basket)
should be replaced. It is not possible to satisfactorily remove the Check Valve itself from the inlet elbow
and this should not be attempted. The shower valve body must be removed from the pre-plumbed
enclosure in order to remove the inlet elbows. See Fig 9 for the location of the parts.
Care should be taken not to lose any of the parts from the drive coupling on the Servicing Valves.
Fig 9.