about xypic : how to draw a turn with double line?

Question

Here is my original code :

\documentclass[10pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{
    amsmath,amssymb, 
}
\usepackage{graphicx}
\usepackage[% xypic
    all,pdf,cmtip,color
]{xy} % xypic
\usepackage[dvipsnames]{xcolor}
% ---------------------------------------------------------
\begin{document}
\(\begin{xy}<1.5cm,0cm>:
(0,0)*{\textsf{Water Tank}};
(0,0)*=<4cm,2cm>[F-]{}*\frm{(}*\frm{)};
% cold water
{(+2  ,-1.5) \PATH ~={**@{=}} ~>{|>*{\NoTips\dir{>}}} `l 
 (+1  ,-1.5) *!U(1.5){\textsf{\color{blue}cold water}}
 (+1  ,-0.5)};
% hot  water
{(-1  ,-0.5) \PATH ~={**@{=}} ~>{|>*{\NoTips\dir{>}}} `d
 (-1  ,-1.5)*!U(1.5){\color{red}\underset{\textsf{(to faucet)}}{\textsf{hot water}}}
 (-2  ,-1.5)}
\end{xy}\)
\end{document}

And it produces this :

how to make the turn area double line , and how to change the color of the arrow ? would you mind explaining the Figure 14 of page 39 of the xyrefer.pdf ? That would be helpful : )