Mitsumi electronic PQHY-P7296TGMU-A Refrigerant piping installation, Pump interlock

2Water quality standard

			Lower mid-range		Tendency
			temperature water system
	Items		Recirculating	Make-up		Scale-
			water		Corrosive
			[20<T<60°C]	water		forming
			[68<T<140°F]
	pH (25˚C) [77°F]		7.0 ~ 8.0	7.0 ~ 8.0
	Electric conductivity	(mS/m) (25°C) [77°F]	30 or less	30 or less
	(∝ s/cm) (25°C) [77°F]		[300 or less]	[300 or less]
	Chloride ion	(mg Cl-/r)	50 or less	50 or less
Standard	Sulfate ion	(mg SO42-/r)	50 or less	50 or less
items	Acid consumption (pH4.8)		50 or less	50 or less
		(mg CaCO3/r)
	Total hardness	(mg CaCO3/r)	70 or less	70 or less
	Calcium hardness	3	50 or less	50 or less
		(mg CaCO /r)
	Ionic silica	(mg SiO2/r)	30 or less	30 or less
Refer-	Iron	(mg Fe/r)	1.0 or less	0.3 or less
ence	Copper	(mg Cu/r)	1.0 or less	0.1 or less
items	Sulfide ion	(mg S2-/r)	not to be	not to be
			detected	detected
	Ammonium ion	4+	0.3 or less	0.1 or less
		(mg NH /r)
	Residual chlorine	(mg Cl/r)	0.25 or less	0.3 or less
	Free carbon dioxide	(mg CO2/r)	0.4 or less	4.0 or less
	Ryzner stability index		–	–

Reference : Guideline of Water Quality for Refrigeration and Air Conditioning Equipment. (JRA GL02E-1994)

3Please consult with a water quality control specialist about water quality control methods and water quality calculations before using anti-corrosive solutions for water quality management.

4When replacing a previously installed air conditioning device (even when only the heat exchanger is being replaced), first conduct a water quality analysis and check for possible corrosion.

Corrosion can occur in cold-water systems even if there has been no prior signs of corrosion.

If the water quality level has dropped, please adjust water quality suffi- ciently before replacing the unit.

7.4. Pump interlock

The heat source unit may become damaged if it is operated with no water circulat- ing through the pipes.

Be sure to interlock unit operation and the water-circuit pump. Use the terminal blocks for interlocking (TB8-3, 4) that can be found on the unit.

In the case of a pump interlock circuit signal connection to the TB8-3, 4, remove the short-circuit wire. Also, to prevent mistaken error detection, resulting from a poor connection, in the pressure valve 63PW, use a low maintained current of 5mA or less.

[Fig. 7.4.1] (P.2)

AShort-circuit wire (Connected before delivery from manufacturer)

BPump interlock circuit connection

GB

8. Refrigerant piping installation
Connecting the piping is a terminal-branch type in which refrigerant piping from	A Residues in commercially available antioxidants may have adverse effects on
the heat source unit is branched at the terminal and connected to each of the
	the equipment. Braze only with non-oxide brazing material. The use of other
indoor units.	brazing material may result in compressor damage.
The method of pipe connection is as follows: flare connection for the indoor units, gas	(Refer to item 9.2. for detailed information on pipe connections and valve op-
pipes for heat source units, flare connection for P72 and brazed connection for P96 ~	erations.)
P168; liquid pipes, flare connection. Note that the branched sections are brazed.	B Never perform heat source unit piping connection work when it is raining.

Warning:

Always use extreme care to prevent the refrigerant gas from leaking while using fire or flame. If the refrigerant gas comes in contact with a flame from any source, such as a gas stove, it breaks down and generates a poisonous gas which can cause gas poisoning. Never weld in an unventilated room. Always conduct an inspection for gas leakage after installation of the refrig- erant piping has been completed.

8.1. Caution

This unit uses refrigerant R410A. Follow the local regulations on materials and pipe thickness when selecting pipes.

1Use the following materials for refrigeration piping.

•Material: Use refrigerant piping made of phosphorus deoxidized copper. In addition, be sure that the inner and outer surfaces of the pipes are clean and free of hazardous sulphur, oxides, dust/dirt, shaving particles, oils, moisture, or any other contaminant.

2Commercially available piping often contains dust and other materials. Always blow it clean with a dry inert gas.

3Use care to prevent dust, water or other contaminants from entering the piping during installation.

4Reduce the number of bending portions as much as possible, and make bend- ing radius as big as possible.

5Always observe the restrictions on the refrigerant piping (such as rated length, the difference between high/low pressures, and piping diameter). Failure to do so can result in equipment failure or a decline in heating/cooling performance.

6Either a lack or an excess of refrigerant causes the unit to make an emergency stop. Charge the system with an appropriate amount of refrigerant. At such a time, always properly charge the unit. When servicing, always check the notes concerning pipe length and amount of additional refrigerant at both locations, the refrigerant volume calculation table on the back of the service panel and the additional refrigerant section on the labels for the combined number of indoor units.

7Use liquid refrigerant to fill the system.

8Never use refrigerant to perform an air purge. Always evacuate using a vacuum pump.

9Always insulate the piping properly. Insufficient insulation will result in a de- cline in heating/cooling performance, water drops from condensation and other such problems.

0When connecting the refrigerant piping, make sure the ball valve of the heat source unit is completely closed (the factory setting) and do not operate it until the refrigerant piping for the heat source and indoor units has been connected, a refrigerant leakage test has been performed and the evacuation process has been completed.

Warning

When installing and moving the unit, do not charge it with refrigerant other than the refrigerant specified on the unit.

- Mixing of a different refrigerant, air, etc. may cause the refrigerant cycle to mal- function and result in severe damage.

Caution:

•Use a vacuum pump with a reverse flow check valve.

-If the vacuum pump does not have a reverse flow check valve, the vacuum pump oil may flow back into the refrigerant cycle and cause deterioration of the refrigerator oil and other trouble.

•Do not use the tools shown below used with conventional refrigerant. (Gauge manifold, charge hose, gas leak detector, check valve, refrigerant charge base, vacuum gauge, refrigerant recovery equipment)

-Mixing of conventional refrigerant and refrigerator oil may cause the refrig- erator oil to deteriorate.

-Mixing of water will cause the refrigerator oil to deteriorate.

-R410A refrigerant does not contain any chlorine. Therefore, gas leak detec- tors for conventional refrigerants will not react to it.

•Manage the tools more carefully than normal.

-If dust, dirt, or water gets in the refrigerant cycle, the refrigerator oil will dete- riorate.

•Never use existing refrigerant piping.

-The large amount of chlorine in conventional refrigerant and refrigerator oil in the existing piping will cause the new refrigerant to deteriorate.

•Store the piping to be used during installation indoors and keep both ends of the piping sealed until just before brazing.

-If dust, dirt, or water gets into the refrigerant cycle, the oil will deteriorate and the compressor may fail.

•Do not use a charging cylinder.

-Using a charging cylinder may cause the refrigerant to deteriorate.

•Do not use special detergents for washing piping.

8.2. Refrigerant piping system

Connection Example

[Fig. 8.2.1] (P.3)

Å Heat source model		ı	Liquid pipe
Ç	Gas pipe	Î Total capacity of indoor units
‰	Model number	Ï	Downstream unit model total

ÌBranch kit model

Ó4-Branching header (Downstream unit model total < 200)

=

¬8-Branching header (Downstream unit model total < 400)

=

Ô10-Branching header (Downstream unit model total < 650)

=

A	Heat source unit	B	First branch
C	Indoor unit	D	Cap	9