• record the temperature of the hot and cold supplies
• record the temperature of the mixed water at the smal-
lest and largest draw-off flow rates
• turn off the cold water supply and record the mixed
water temperature and the maximum temperature
achieved
The values should not be greater than 2°C of the
nominal set point.
9. Maintenance
9.1. General information
Most domestic water supplies contain calcium which will
separate out when the water is heated in a system.
The degree and speed of scaling depends, amongst other
factors, on water flow rates, system design, the degree of
hardness of the water and the temperature to which it is
heated.
Over a period, scale may form within the valve, particularly at
the hot inlet where the water is hottest and this may eventu-
ally prevent one or more ports from closing fully and thereby
impair the temperature control.
Descaling of the mixing valve then becomes necessary.
Because circumstances differ between installations, it is not
possible to give a definitive water hardness level which will
affect the mixing valve within a certain time period.
Simple scale protection of the incoming water supply on any
system will always provide benefits in extending the efficient
operating life of thermostatic mixing valves and other fittings
before service is required.
Scale protection is essential in applications where
water is particularly hard.
If purpose made measuring equipment is not readily avai-
lable, a good guide to hardness can be established by
checking site experience with speed of scale build up in
kettles or coffee machines.
9.2. Inspection
Following commissioning, in-service tests should be carried
out at 6-8 weeks and 12-15 weeks.
1. If no significant changes (i.e. ≤ 1K) occur in either test, a
further inservice test should be carried out at 24 to 28
weeks after commissioning.
2. If small changes (i.e. 1 to 2K) occur in one test necessita-
ting adjustment, a further in-service test should be carried
out at 24 to 28 weeks after commissioning.
3. If small changes (i.e. 1 to 2K) occur in both tests necessi-
tating adjustment, a further in-service test should be
carried out at 18 to 21 weeks after commissioning.
4. If significant changes (i.e. > 2K) occur in either test neces-
sitating service work, a further in-service test should be
carried out at 18 to 21 weeks after commissioning
The general principle to be observed after the first 2 or
3 in-service tests is that the intervals of future tests
should be set to those which previous tests have
shown can be achieved with no more than a small
change in mixed water temperature.
MU1H-1358GE23 R1020
GB
9.3. Maintenance
It is recommended that the mixing valves are
inspected on a regular basis, at least annually, or more
frequently if performance is impaired, to ensure they
are working correctly and that dirt ingress into the
system does not cause a loss in performance of the
mixing valve.
Please note that during servicing the valve piston
should be greased with an approved (WRAS) silicon
lubricant.
If required, a Honeywell Home service kit is available for
cart-
ridge replacement.
1. Prior to servicing, the mixed water temperature must be
recorded. Should the temperature be 2°C greater than
the nominal setting the following should be checked
before dismantling the valve
• Check strainers are clean
• Ensure check valves are in good working order
• Check isolating valves are fully open
2. If these checks are satisfactory then the Honeywell
Home service kit is available for cartridge replacement
(sepa- rate instructions in the service kit detail this
procedure).
3. Set mix water temperature
10. Disposal
• Dezincification resistant brass housing, nickel plated
• Dezincification resistant brass connection fittings, nickel
plated (not in TM50SOLAR)
• Moving parts of high-quality, scale-resistant synthetic
material
• High quality-synthetic material adjustment knob
• Stainless-steel spring
• Protective cap made of transparent plastic (not in
TM50SOLAR)
Observe the local requirements regarding correct waste
recycling/disposal!
11. Spare Parts
1
Control valve, complete
for TM50SOLAR
for TM200SOLAR TM200A-30/60
for TM300SOLAR TM300A-30/60
6
TM50A-30/60
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