8
TMV3 ART 33 Screwed Rev 1
Note 1
•
46°C is the maximum mixed water temperature from the bath tap. The maximum
temperature takes account of the allowable temperature tolerances inherent in
thermostatic mixing valves and temperature losses in metal baths. It is not a safe bathing
temperature for adults or children.
•
The British Burns Association recommends 37 to 37.5°C as a comfortable bathing
temperature for children. In premises covered by the Care Standards Act 2000,
the maximum mixed water outlet temperature is 43°C.
8.
Maintenance & In-Service Testing
•
The purpose of in-service testing is to regularly monitor and record the performance of the
thermostatic mixing valve. Deterioration in performance can indicate the need for service
work on the valve and/or water supply.
•
Carry out the test sequence using the same or equivalent equipment used for
commissioning the valve.
•
If the mixed water temperature has changed significantly from the previous test results
(e.g. >1°C), record the change and before re-adjusting the mixed water temperature carry
out the following checks;
•
All in-line or integral filters are clean.
•
Any in-line or integral non-return valves or other anti-back siphonage devices are in
good working condition.
•
Any isolation valves are fully open.
•
With an acceptable mixed water temperature, complete the test sequence as per section 7
of this document.
•
In the absence of any other instruction or guidance, it is recommended that In-Service
Tests are carried out as per the table below. If the temperature is outside of the expected
range it will be necessary to remove and clean the valve in accordance with the
instructions in the table below: -
Temperature Variation (°C)
Comment
Service Frequency (Weeks)
+/- 1°C
N/A
24 – 28 Weeks
+/- 1°C – 2°C
In either one period
24 – 28 Weeks
+/- 1°C – 2°C
In both periods
18 – 21 Weeks
+/- Exceed 2°C
In either period
18 – 21 Weeks
•
If there is a residual flow during the commissioning or bi-annual verification (cold
water supply isolation test) then this is acceptable providing the temperature of the water
seeping from the valve is no more than 2°C above the designated maximum mixed water
