TTHERM GEO TVA series, Installation & Operating Instructions Manual

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12/06/2012 11 GI202
Figure 1
Horizontal Closed Loop
Mechanical Installation Overview
This TTHERM GEO series unit cannot correct airflow problems inherent within the duct work system. The
following items should be carefully considered and properly followed for all installations:
Examination of the existing forced air furnace
– Prior to starting this installation, examine the total furnace
system and make necessary comments or recommendations to the homeowner. Remember, if a marginal
condition exists within the existing duct work system, the installation of a geothermal heat pump will not cure
PRE-EXISTING conditions. Consider such items as adequate cold air return and supply duct. Inspect and count
supply and return registers for size and number.
Heating capacity
– Size the geothermal heat pump according to the normal heating requirements as the building
exists today. Do not necessarily match to the existing furnace nameplate because it may be oversized. The
geothermal heat pump should be properly sized for the heat loss of the house. Heat loss and heat gain audits
should be done to determine proper equipment sizing.
Flexible duct connections
– Flex duct connections are required for both the supply and return duct connections
and metal duct systems.
Other plenum equipment
– Auxiliary equipment such as humidifiers, zone plenum dampers, etc., located
within the plenum which may cause a non-uniform airflow issues may have to be removed if they cause to great
reduction to system airflow.
Comment – zone dampers cause back pressure on the blower and overall reduced airflow. Reduced airflow
can cause the geothermal unit to perform poorly or in some cases cause icing or freeze ups in the air coil. If
the smallest zone cannot handle the minimum CFM requirements of the heat pump a dump zone and/or allow
air flow to bypass to other zones.
Insufficient cold air return capacity
– Installation experience indicates this is a major concern. In fact, it
could represent a problem in as many as 60% of the installations, especially if there is a requirement to increase
airflow when the existing cold air return capacity is already undersized or restricted. Check the static pressure
within the return cabinet or the suction at the filter cabinet door. Do not assume because there is a register on
the wall, the hole behind the register or the passageways are equal to this register. Sharp offsets and transitions
in the cold air return system often cause severe restrictions. Expect to add additional registers or a relief register
in the main cold air return duct. Best practice would include both high and low return registers.
Closed Loop Applications
– Closed loop system re-circulates the same water/antifreeze solution through a
closed system of underground high-density polyethylene pipe. As the solution passes
through the pipe it collects heat (in the heating mode) that is being transferred
from the relatively warm surrounding soil through the pipe and into the relatively
cold solution. The solution is circulated back to the heat pump that extracts its
heat and then returns to the ground to absorb more heat from the earth. Earth
loops must be sized properly for each particular geographic area and individual
capacity requirements.
The TTHERM GEO series heat pumps are designed to operate on either
vertical
or horizontal closed loop applications.
(Figures 1 & 2) Vertical loops are
typically installed with a well drilling rig up to 200 feet (61 meters) deep or more. Horizontal systems are
typically installed with excavating or trenching equipment approximately six to eight feet (1.8 – 2.4 meters)
deep, depending on geographic location and length of pipe used. Horizontal bored loops are typically installed
15 feet deep.
Lake or Pond Loops
– Closed loop systems may also be used in lakes or rivers to
supply a heat source to the heat pump. Typically a loop consisting of geothermal
pipe can be designed and placed in an area at least 12ft (3.7 meters) with some water
currents present. In any lake or pond, municipal and local codes must be observed
in regards to a lake or pond loop. The use of an environmentally friendly loop fluid
like Propylene Glycol should be considered in the event damage should ever occur
to the loop.
Consult sales at TTHERM GEO or an IGSHPA or CGC certified installer for proper
loop design and installation. State and local codes apply. Figure 2
Vertical Closed Loop